Fix shift count truncate problem for loongson.

From-SVN: r163799

2 files changed, 21 insertions, 3 deletions

diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index 052e805..3fe7f8b 100644
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -16338,6 +16338,20 @@ void mips_function_profiler (FILE *file)
     fprintf (file, "\tmove\t%s,%s\n", reg_names[STATIC_CHAIN_REGNUM],
 	     reg_names[2]);
 }
+
+/* Implement TARGET_SHIFT_TRUNCATION_MASK.  We want to keep the default
+   behaviour of TARGET_SHIFT_TRUNCATION_MASK for non-vector modes even
+   when TARGET_LOONGSON_2EF is true.  */
+
+static unsigned HOST_WIDE_INT
+mips_shift_truncation_mask (enum machine_mode mode)
+{
+  if (TARGET_LOONGSON_2EF && VECTOR_MODE_P (mode))
+    return 0;
+
+  return GET_MODE_BITSIZE (mode) - 1;
+}
+
 
 /* Initialize the GCC target structure.  */
 #undef TARGET_ASM_ALIGNED_HI_OP
@@ -16546,6 +16560,9 @@ void mips_function_profiler (FILE *file)
 #undef TARGET_ASM_OUTPUT_SOURCE_FILENAME
 #define TARGET_ASM_OUTPUT_SOURCE_FILENAME mips_output_filename
 
+#undef TARGET_SHIFT_TRUNCATION_MASK
+#define TARGET_SHIFT_TRUNCATION_MASK mips_shift_truncation_mask
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-mips.h"
diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 4dd86d4..74bf3d25 100644
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -2423,9 +2423,10 @@ typedef struct mips_args {
    (often extended) would be needed for byte accesses.  */
 #define SLOW_BYTE_ACCESS (!TARGET_MIPS16)
 
-/* Define this to be nonzero if shift instructions ignore all but the low-order
-   few bits.  */
-#define SHIFT_COUNT_TRUNCATED 1
+/* Standard MIPS integer shifts truncate the shift amount to the
+   width of the shifted operand.  However, Loongson vector shifts
+   do not truncate the shift amount at all.  */
+#define SHIFT_COUNT_TRUNCATED (!TARGET_LOONGSON_2EF)
 
 /* Value is 1 if truncating an integer of INPREC bits to OUTPREC bits
    is done just by pretending it is already truncated.  */