re PR rtl-optimization/37544 (Conversion double -> unsigned long long ->…

re PR rtl-optimization/37544 (Conversion double -> unsigned long long -> unsigned -> double gives wrong results)

	PR rtl-optimization/37544
	* regrename.c (maybe_mode_change): Exit early when copy_mode
	is narrower than orig_mode and narrower than new_mode.

testsuite/ChangeLog:

	PR rtl-optimization/37544
	* gcc.dg/pr37544.c: New test.

From-SVN: r140446

gcc/regrename.c

@@ -1314,6 +1314,10 @@ maybe_mode_change (enum machine_mode orig_mode, enum machine_mode copy_mode,
 		   enum machine_mode new_mode, unsigned int regno,
 		   unsigned int copy_regno ATTRIBUTE_UNUSED)
 {
+  if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode)
+      && GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
+    return NULL_RTX;
+
   if (orig_mode == new_mode)
     return gen_rtx_raw_REG (new_mode, regno);
   else if (mode_change_ok (orig_mode, new_mode, regno))

gcc/testsuite/ChangeLog

+2008-09-18  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR rtl-optimization/37544
+	* gcc.dg/pr37544.c: New test.
+
 2008-09-17  Janis Johnson  <janis187@us.ibm.com>
 
 	PR testsuite/25241

gcc/testsuite/gcc.dg/pr37544.c

+/* { dg-do run } */
+/* { dg-options "-O2" } */
+/* { dg-options "-O2 -msse2 -mtune=core2 -mfpmath=387" { target { i?86-*-* x86_64-*-* } } } */
+
+#ifdef __i386__
+#include "cpuid.h"
+#endif
+
+extern void abort (void);
+
+int main(void)
+{
+  double arr[1000];
+  double a, b;
+
+  int i;
+
+#ifdef __i386__
+  unsigned int eax, ebx, ecx, edx;
+ 
+  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+    return 0;
+
+  /* Run SSE2 test only if host has SSE2 support.  */
+  if (!(edx & bit_SSE2))
+    return 0;
+#endif
+
+  for (i = 0; i < 1000; i++)
+    arr[i] = 4294967296.0 + (double)i;
+
+  a = arr[0];
+  b = (unsigned int)((unsigned long long int)a % 4294967296ULL);
+
+  if (b >= 4294967296.0)
+    abort ();
+
+  return 0;
+}