PR26449, PR26450 UBSAN: frv-ibld.c:135 left shift

Eh well, I guess the code didn't quite live up to the comment.

	PR 26449
	PR 26450
	* cgen-ibld.in (insert_1): Use 1UL in forming mask.
	(extract_normal): Likewise.
	(insert_normal): Likewise, and move past zero length test.
	(put_insn_int_value): Handle mask for zero length, use 1UL.
	* bpf-ibld.c, * epiphany-ibld.c, * fr30-ibld.c, * frv-ibld.c,
	* ip2k-ibld.c, * iq2000-ibld.c, * lm32-ibld.c, * m32c-ibld.c,
	* m32r-ibld.c, * mep-ibld.c, * mt-ibld.c, * or1k-ibld.c,
	* xc16x-ibld.c, * xstormy16-ibld.c: Regenerate.

16 files changed, 133 insertions, 90 deletions

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 71826bd..6e7b8f4 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,16 @@
+2020-08-28  Alan Modra  <amodra@gmail.com>
+
+	PR 26449
+	PR 26450
+	* cgen-ibld.in (insert_1): Use 1UL in forming mask.
+	(extract_normal): Likewise.
+	(insert_normal): Likewise, and move past zero length test.
+	(put_insn_int_value): Handle mask for zero length, use 1UL.
+	* bpf-ibld.c, * epiphany-ibld.c, * fr30-ibld.c, * frv-ibld.c,
+	* ip2k-ibld.c, * iq2000-ibld.c, * lm32-ibld.c, * m32c-ibld.c,
+	* m32r-ibld.c, * mep-ibld.c, * mt-ibld.c, * or1k-ibld.c,
+	* xc16x-ibld.c, * xstormy16-ibld.c: Regenerate.
+
 2020-08-28  Cooper Qu  <cooper.qu@linux.alibaba.com>
 
 	* csky-dis.c (CSKY_DEFAULT_ISA): Define.
diff --git a/opcodes/bpf-ibld.c b/opcodes/bpf-ibld.c
index 392dceb..0070e41 100644
--- a/opcodes/bpf-ibld.c
+++ b/opcodes/bpf-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/cgen-ibld.in b/opcodes/cgen-ibld.in
index ae9d20d..7829822 100644
--- a/opcodes/cgen-ibld.in
+++ b/opcodes/cgen-ibld.in
@@ -84,13 +84,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -130,13 +130,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -313,7 +315,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -490,7 +492,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/epiphany-ibld.c b/opcodes/epiphany-ibld.c
index 4a974ed..27f0fab 100644
--- a/opcodes/epiphany-ibld.c
+++ b/opcodes/epiphany-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/fr30-ibld.c b/opcodes/fr30-ibld.c
index 6816154..8cc7020 100644
--- a/opcodes/fr30-ibld.c
+++ b/opcodes/fr30-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/frv-ibld.c b/opcodes/frv-ibld.c
index 43bccba..2a7fcb8 100644
--- a/opcodes/frv-ibld.c
+++ b/opcodes/frv-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/ip2k-ibld.c b/opcodes/ip2k-ibld.c
index 605d0bd..18c2fed 100644
--- a/opcodes/ip2k-ibld.c
+++ b/opcodes/ip2k-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/iq2000-ibld.c b/opcodes/iq2000-ibld.c
index 2a87c70..cad26e2 100644
--- a/opcodes/iq2000-ibld.c
+++ b/opcodes/iq2000-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/lm32-ibld.c b/opcodes/lm32-ibld.c
index 2b0efda..48e894a 100644
--- a/opcodes/lm32-ibld.c
+++ b/opcodes/lm32-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/m32c-ibld.c b/opcodes/m32c-ibld.c
index 6ad4da9..67bfb48 100644
--- a/opcodes/m32c-ibld.c
+++ b/opcodes/m32c-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/m32r-ibld.c b/opcodes/m32r-ibld.c
index 559f471..8e1a7de 100644
--- a/opcodes/m32r-ibld.c
+++ b/opcodes/m32r-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/mep-ibld.c b/opcodes/mep-ibld.c
index 66a30e1..3de7ade 100644
--- a/opcodes/mep-ibld.c
+++ b/opcodes/mep-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/mt-ibld.c b/opcodes/mt-ibld.c
index 683b76b..924fc90 100644
--- a/opcodes/mt-ibld.c
+++ b/opcodes/mt-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/or1k-ibld.c b/opcodes/or1k-ibld.c
index 7b89260..576a139 100644
--- a/opcodes/or1k-ibld.c
+++ b/opcodes/or1k-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/xc16x-ibld.c b/opcodes/xc16x-ibld.c
index b2802fe..ed51a1b 100644
--- a/opcodes/xc16x-ibld.c
+++ b/opcodes/xc16x-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */
diff --git a/opcodes/xstormy16-ibld.c b/opcodes/xstormy16-ibld.c
index eaffbee..06f036f 100644
--- a/opcodes/xstormy16-ibld.c
+++ b/opcodes/xstormy16-ibld.c
@@ -85,13 +85,13 @@ insert_1 (CGEN_CPU_DESC cd,
 	  int word_length,
 	  unsigned char *bufp)
 {
-  unsigned long x,mask;
+  unsigned long x, mask;
   int shift;
 
   x = cgen_get_insn_value (cd, bufp, word_length, cd->endian);
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
   if (CGEN_INSN_LSB0_P)
     shift = (start + 1) - length;
   else
@@ -131,13 +131,15 @@ insert_normal (CGEN_CPU_DESC cd,
 	       CGEN_INSN_BYTES_PTR buffer)
 {
   static char errbuf[100];
-  /* Written this way to avoid undefined behaviour.  */
-  unsigned long mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  unsigned long mask;
 
   /* If LENGTH is zero, this operand doesn't contribute to the value.  */
   if (length == 0)
     return NULL;
 
+  /* Written this way to avoid undefined behaviour.  */
+  mask = (1UL << (length - 1) << 1) - 1;
+
   if (word_length > 8 * sizeof (CGEN_INSN_INT))
     abort ();
 
@@ -314,7 +316,7 @@ put_insn_int_value (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
     {
       int shift = insn_length - length;
       /* Written this way to avoid undefined behaviour.  */
-      CGEN_INSN_INT mask = (((1L << (length - 1)) - 1) << 1) | 1;
+      CGEN_INSN_INT mask = length == 0 ? 0 : (1UL << (length - 1) << 1) - 1;
 
       *buf = (*buf & ~(mask << shift)) | ((value & mask) << shift);
     }
@@ -491,7 +493,7 @@ extract_normal (CGEN_CPU_DESC cd,
 #endif /* ! CGEN_INT_INSN_P */
 
   /* Written this way to avoid undefined behaviour.  */
-  mask = (((1L << (length - 1)) - 1) << 1) | 1;
+  mask = (1UL << (length - 1) << 1) - 1;
 
   value &= mask;
   /* sign extend? */