[PATCH, PR61605, 2/2] Use fuse-caller-save info in pass_cprop_hardreg

[Tom de Vries <Tom_deVries at mentor dot com>]

Eric,

this patch is the second half of the fix for PR61605.

It make sure in pass_cprop_hardreg that, if available we use the call-specific 
information provided by fuse-caller-save, rather than the generic 
regs_invalidated_by_call info.

The 2 patches together allow an insn to removed from the 
gcc.target/i386/fuse-caller-save.c testcase, which is updated accordingly in 
this patch.

Bootstrapped and reg-tested on x86_64.

OK for trunk?

Thanks,
- Tom

2014-10-13  Tom de Vries  <tom@codesourcery.com>

	PR rtl-optimization/61605
	* regcprop.c (copyprop_hardreg_forward_1): Use
	regs_invalidated_by_this_call instead of regs_invalidated_by_call.

	* gcc.target/i386/fuse-caller-save.c: Update addition check.  Add movl
	absence check.

diff --git a/gcc/regcprop.c b/gcc/regcprop.c
index c71de98..304820f 100644
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -1000,6 +1000,7 @@ copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
 	  unsigned int set_nregs = 0;
 	  unsigned int regno;
 	  rtx exp;
+	  HARD_REG_SET regs_invalidated_by_this_call;
 
 	  for (exp = CALL_INSN_FUNCTION_USAGE (insn); exp; exp = XEXP (exp, 1))
 	    {
@@ -1018,8 +1019,11 @@ copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
 		}
 	    }
 
+	  get_call_reg_set_usage (insn,
+				  &regs_invalidated_by_this_call,
+				  regs_invalidated_by_call);
 	  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
-	    if ((TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)
+	    if ((TEST_HARD_REG_BIT (regs_invalidated_by_this_call, regno)
 		 || HARD_REGNO_CALL_PART_CLOBBERED (regno, vd->e[regno].mode))
 		&& (regno < set_regno || regno >= set_regno + set_nregs))
 	      kill_value_regno (regno, 1, vd);
diff --git a/gcc/testsuite/gcc.target/i386/fuse-caller-save.c b/gcc/testsuite/gcc.target/i386/fuse-caller-save.c
index 7e2b11d..a6e8f1c 100644
--- a/gcc/testsuite/gcc.target/i386/fuse-caller-save.c
+++ b/gcc/testsuite/gcc.target/i386/fuse-caller-save.c
@@ -20,5 +20,13 @@ foo (int y)
 /* { dg-final { scan-assembler-not "push"  } } */
 /* { dg-final { scan-assembler-not "pop"  } } */
 
-/* Check that addition uses dx. */
-/* { dg-final { scan-assembler-times "addl\t%\[re\]?dx, %\[re\]?ax" 1 } } */
+/* PR61605.  If the first argument register and the return register differ, then
+   bar leaves the first argument register intact.  That means in foo that the
+   first argument register still contains y after bar has been called, and
+   there's no need to copy y to a different register before the call, to be able
+   to use it after the call.
+   Check that the copy is absent.  */
+/* { dg-final { scan-assembler-not "movl" { target { ! ia32 } } } } */
+
+/* Check that addition uses di (in case of no copy) or dx (in case of copy). */
+/* { dg-final { scan-assembler-times "addl\t%\[re\]?d\[ix\], %\[re\]?ax" 1 } } */
-- 
1.9.1