[PATCH, PR61446] Fix mode for register copy in REE pass

[Ilya Enkovich]

On 11 Jun 14:59, Uros Bizjak wrote:
> On Tue, Jun 10, 2014 at 3:45 PM, Dominique Dhumieres <dominiq@lps.ens.fr> wrote:
> >> This patch fixes PR61446. ...
> >
> > Confirmed, it also allows to bootstrap Core* targets.
> > Could it be reviewed and committed ASAP?
> 
> > 2014-06-09  Ilya Enkovich  <ilya.enkovich@intel.com>
> >
> > PR 61446
> > * ree.c (find_and_remove_re): Narrow mode for register copy
> > if required.
> 
> Please also add the testcase form the PR.
> 
> (I am not RTL reviewer, so I can't approve the patch).
> 
> Uros.

Hi,

rgis one is the same but with testcase added.

Bootstrapped and tested on linux-x86_64.

Thanks,
Ilya
--
gcc/

2014-06-11  Ilya Enkovich  <ilya.enkovich@intel.com>

	PR 61446
	* ree.c (find_and_remove_re): Narrow mode for register copy
	if required.

gcc/testsuite/

2014-06-11  Ilya Enkovich  <ilya.enkovich@intel.com>

	 * gcc.target/i386/pr61446.c : New.


diff --git a/gcc/ree.c b/gcc/ree.c
index ade413e..6d34764 100644
--- a/gcc/ree.c
+++ b/gcc/ree.c
@@ -1088,14 +1088,24 @@ find_and_remove_re (void)
       /* Use the mode of the destination of the defining insn
 	 for the mode of the copy.  This is necessary if the
 	 defining insn was used to eliminate a second extension
-	 that was wider than the first.  */
+	 that was wider than the first.  Truncate mode if it is
+	 too wide for destination reg.  */
       rtx sub_rtx = *get_sub_rtx (def_insn);
       rtx pat = PATTERN (curr_insn);
-      rtx new_dst = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
-				 REGNO (XEXP (SET_SRC (pat), 0)));
-      rtx new_src = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
-				 REGNO (SET_DEST (pat)));
-      rtx set = gen_rtx_SET (VOIDmode, new_dst, new_src);
+      unsigned int regno = REGNO (XEXP (SET_SRC (pat), 0));
+      enum machine_mode mode = GET_MODE (SET_DEST (sub_rtx));
+      rtx new_dst, new_src, set;
+
+      if (HARD_REGNO_NREGS (regno, mode) != 1)
+	{
+	  mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (mode));
+	  while (HARD_REGNO_NREGS (regno, GET_MODE_WIDER_MODE (mode)) == 1)
+	    mode = GET_MODE_WIDER_MODE (mode);
+	}
+
+      new_dst = gen_rtx_REG (mode, REGNO (XEXP (SET_SRC (pat), 0)));
+      new_src = gen_rtx_REG (mode, REGNO (SET_DEST (pat)));
+      set = gen_rtx_SET (VOIDmode, new_dst, new_src);
       emit_insn_after (set, def_insn);
     }
 
diff --git a/gcc/testsuite/gcc.target/i386/pr61446.c b/gcc/testsuite/gcc.target/i386/pr61446.c
new file mode 100644
index 0000000..8537cdb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr61446.c
@@ -0,0 +1,14 @@
+/* PR rtl-optimization/61446 */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -m32 -march=corei7" } */
+
+unsigned long long
+foo (float a)
+{
+  const double dfa = a;
+  const unsigned int hi = dfa / 0x1p32f;
+  const unsigned int lo = dfa - (double) hi * 0x1p32f;
+
+  return ((unsigned long long) hi << (4 * (8))) | lo;
+}