[PATCH] loop-invariant: JUMP_INSNs aren't loop invariant [PR97954]

[PATCH] loop-invariant: JUMP_INSNs aren't loop invariant [PR97954]

[Jakub Jelinek]

Hi!

The following testcase ICEs because loop invariant motion moves asm goto
with a single output as invariant.
Normally, jumps aren't really moved, because if they are single set,
they have their SET_DEST (pc) and pc_rtx has VOIDmode on which one of the
functions find_invariant_insn calls bails out.  The code already punts on
insns that can throw or trap.  And for asm goto without outputs, it isn't
single set, or asm goto with two or more outputs it isn't single set either.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2020-12-01  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/97954
	* loop-invariant.c (find_invariant_insn): Punt on JUMP_P insns.

	* gcc.dg/pr97954.c: New test.

--- gcc/loop-invariant.c.jj	2020-01-12 11:54:36.000000000 +0100
+++ gcc/loop-invariant.c	2020-11-30 09:56:37.022696142 +0100
@@ -1099,6 +1099,10 @@ find_invariant_insn (rtx_insn *insn, boo
   if (HAVE_cc0 && sets_cc0_p (insn))
     return;
 
+  /* Jumps have control flow side-effects.  */
+  if (JUMP_P (insn))
+    return;
+
   set = single_set (insn);
   if (!set)
     return;
--- gcc/testsuite/gcc.dg/pr97954.c.jj	2020-11-30 10:31:54.870891248 +0100
+++ gcc/testsuite/gcc.dg/pr97954.c	2020-11-30 10:31:08.875407984 +0100
@@ -0,0 +1,12 @@
+/* PR rtl-optimization/97954 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int
+foo (void)
+{
+  int x;
+ lab:
+  asm goto ("": "=r" (x) : : : lab);
+  return x;
+}

	Jakub

Re: [PATCH] loop-invariant: JUMP_INSNs aren't loop invariant [PR97954]

[Richard Biener]

On Tue, 1 Dec 2020, Jakub Jelinek wrote:

> Hi!
> 
> The following testcase ICEs because loop invariant motion moves asm goto
> with a single output as invariant.
> Normally, jumps aren't really moved, because if they are single set,
> they have their SET_DEST (pc) and pc_rtx has VOIDmode on which one of the
> functions find_invariant_insn calls bails out.  The code already punts on
> insns that can throw or trap.  And for asm goto without outputs, it isn't
> single set, or asm goto with two or more outputs it isn't single set either.
> 
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?

OK.

Thanks,
Richard.

> 2020-12-01  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/97954
> 	* loop-invariant.c (find_invariant_insn): Punt on JUMP_P insns.
> 
> 	* gcc.dg/pr97954.c: New test.
> 
> --- gcc/loop-invariant.c.jj	2020-01-12 11:54:36.000000000 +0100
> +++ gcc/loop-invariant.c	2020-11-30 09:56:37.022696142 +0100
> @@ -1099,6 +1099,10 @@ find_invariant_insn (rtx_insn *insn, boo
>    if (HAVE_cc0 && sets_cc0_p (insn))
>      return;
>  
> +  /* Jumps have control flow side-effects.  */
> +  if (JUMP_P (insn))
> +    return;
> +
>    set = single_set (insn);
>    if (!set)
>      return;
> --- gcc/testsuite/gcc.dg/pr97954.c.jj	2020-11-30 10:31:54.870891248 +0100
> +++ gcc/testsuite/gcc.dg/pr97954.c	2020-11-30 10:31:08.875407984 +0100
> @@ -0,0 +1,12 @@
> +/* PR rtl-optimization/97954 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +int
> +foo (void)
> +{
> +  int x;
> + lab:
> +  asm goto ("": "=r" (x) : : : lab);
> +  return x;
> +}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)