re PR rtl-optimization/18928 (ice on valid code with -O2 -fPIC)

	PR rtl-optimization/18928
	* simplify_rtx.c (plus_minus_operand_p): New function to encode
	the test for suitable operands for calls to simplify_plus_minus.
	Only allow (CONST (PLUS x y)) if both x and y are CONSTANT_P.
	(simplify_binary_operation): Use plus_minus_operand_p.

	* gcc.dg/pr18928-1.c: New test case.

From-SVN: r92109

4 files changed, 50 insertions, 12 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e12edaf..52699a0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2004-12-13  Roger Sayle  <roger@eyesopen.com>
+
+	PR rtl-optimization/18928
+	* simplify_rtx.c (plus_minus_operand_p): New function to encode
+	the test for suitable operands for calls to simplify_plus_minus.
+	Only allow (CONST (PLUS x y)) if both x and y are CONSTANT_P.
+	(simplify_binary_operation): Use plus_minus_operand_p.
+
 2004-12-13  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR tree-opt/16951
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 2ac5661..3685bbf 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -50,6 +50,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  ((((HOST_WIDE_INT) low) < 0) ? ((HOST_WIDE_INT) -1) : ((HOST_WIDE_INT) 0))
 
 static rtx neg_const_int (enum machine_mode, rtx);
+static bool plus_minus_operand_p (rtx);
 static int simplify_plus_minus_op_data_cmp (const void *, const void *);
 static rtx simplify_plus_minus (enum rtx_code, enum machine_mode, rtx,
 				rtx, int);
@@ -1567,12 +1568,8 @@ simplify_binary_operation (enum rtx_code code, enum machine_mode mode,
 	     and subtle programs can break if operations are associated.  */
 
 	  if (INTEGRAL_MODE_P (mode)
-	      && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
-		  || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS
-		  || (GET_CODE (op0) == CONST
-		      && GET_CODE (XEXP (op0, 0)) == PLUS)
-		  || (GET_CODE (op1) == CONST
-		      && GET_CODE (XEXP (op1, 0)) == PLUS))
+	      && (plus_minus_operand_p (op0)
+		  || plus_minus_operand_p (op1))
 	      && (tem = simplify_plus_minus (code, mode, op0, op1, 0)) != 0)
 	    return tem;
 
@@ -1724,12 +1721,8 @@ simplify_binary_operation (enum rtx_code code, enum machine_mode mode,
 	     and subtle programs can break if operations are associated.  */
 
 	  if (INTEGRAL_MODE_P (mode)
-	      && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
-		  || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS
-		  || (GET_CODE (op0) == CONST
-		      && GET_CODE (XEXP (op0, 0)) == PLUS)
-		  || (GET_CODE (op1) == CONST
-		      && GET_CODE (XEXP (op1, 0)) == PLUS))
+	      && (plus_minus_operand_p (op0)
+		  || plus_minus_operand_p (op1))
 	      && (tem = simplify_plus_minus (code, mode, op0, op1, 0)) != 0)
 	    return tem;
 
@@ -2677,6 +2670,18 @@ simplify_plus_minus (enum rtx_code code, enum machine_mode mode, rtx op0,
   return result;
 }
 
+/* Check whether an operand is suitable for calling simplify_plus_minus.  */
+static bool
+plus_minus_operand_p (rtx x)
+{
+  return GET_CODE (x) == PLUS
+         || GET_CODE (x) == MINUS
+	 || (GET_CODE (x) == CONST
+	     && GET_CODE (XEXP (x, 0)) == PLUS
+	     && CONSTANT_P (XEXP (XEXP (x, 0), 0))
+	     && CONSTANT_P (XEXP (XEXP (x, 0), 1)));
+}
+
 /* Like simplify_binary_operation except used for relational operators.
    MODE is the mode of the result. If MODE is VOIDmode, both operands must
    not also be VOIDmode.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 647411e..636869b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2004-12-13  Roger Sayle  <roger@eyesopen.com>
+
+	PR rtl-optimization/18928
+	* gcc.dg/pr18928-1.c: New test case.
+
 2004-12-13  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR tree-opt/16951
diff --git a/gcc/testsuite/gcc.dg/pr18928-1.c b/gcc/testsuite/gcc.dg/pr18928-1.c
new file mode 100644
index 0000000..3a0107d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr18928-1.c
@@ -0,0 +1,20 @@
+/* PR rtl-optimization/18928 */
+/* { dg-do compile { target i?86-*-linux* } } */
+/* { dg-options "-O2 -fPIC" } */
+
+const char *toHex( unsigned short u )
+{
+  static char hexVal[5];
+  int i = 3;
+  while ( i >= 0 ) {
+    unsigned short hex = (u & 0x000f);
+    if ( hex < 0x0a )
+      hexVal[i] = '0'+hex;
+    else
+      hexVal[i] = 'A'+(hex-0x0a);
+    i--;
+  }
+  hexVal[4] = '\0';
+  return hexVal;
+}
+