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* [PATCH] arm: Fix ICE caused by arm_gen_discompare_reg [PR94292]
@ 2020-03-25  7:21 Jakub Jelinek
  2020-03-25 17:51 ` Richard Earnshaw (lists)
  0 siblings, 1 reply; 2+ messages in thread
From: Jakub Jelinek @ 2020-03-25  7:21 UTC (permalink / raw)
  To: Richard Earnshaw, Ramana Radhakrishnan, Kyrylo Tkachov; +Cc: gcc-patches

Hi!

The following testcase ICEs, because arm_gen_discompare_reg creates invalid
RTL which then propagates into DEBUG_INSNs and ICEs while handling them.
The problem is that this function emits
(insn 18 17 19 2 (set (reg:CC_DNE 100 cc)
        (compare (ior:SI (ne:SI (subreg:SI (reg:DI 129) 0)
                    (subreg:SI (reg:DI 114 [ _2 ]) 0))
                (ne:SI (subreg:SI (reg:DI 129) 4)
                    (subreg:SI (reg:DI 114 [ _2 ]) 4)))
            (const_int 0 [0]))) "pr94292.c":7:11 325 {*cmp_ior}
     (nil))
and the invalid thing is that the COMPARE has VOIDmode.  Setting a
non-VOIDmode SET_DEST to VOIDmode SET_SRC is only valid if the SET_SRC is
CONST_INT/CONST_DOUBLE.
The following patch fixes it by giving the COMPARE the same mode as it gives
to the SET_DEST cc register.

Bootstrapped/regtested on armv7hl-linux-gnueabi, ok for trunk?

2020-03-25  Jakub Jelinek  <jakub@redhat.com>

	PR target/94292
	* config/arm/arm.c (arm_gen_discompare_reg): Set mode of COMPARE to
	mode rather than VOIDmode.

	* gcc.dg/pr94292.c: New test.

--- gcc/config/arm/arm.c.jj	2020-03-18 19:25:33.000000000 +0100
+++ gcc/config/arm/arm.c	2020-03-24 13:14:38.568689174 +0100
@@ -15763,7 +15763,7 @@ arm_gen_dicompare_reg (rtx_code code, rt
 	cc_reg = gen_rtx_REG (mode, CC_REGNUM);
 
 	emit_insn (gen_rtx_SET (cc_reg,
-				gen_rtx_COMPARE (VOIDmode, conjunction,
+				gen_rtx_COMPARE (mode, conjunction,
 						 const0_rtx)));
 	return cc_reg;
       }
--- gcc/testsuite/gcc.dg/pr94292.c.jj	2020-03-24 13:07:12.694449518 +0100
+++ gcc/testsuite/gcc.dg/pr94292.c	2020-03-24 13:06:53.720737198 +0100
@@ -0,0 +1,13 @@
+/* PR target/94292 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -g -fno-tree-dce" } */
+
+unsigned short a;
+unsigned long long b;
+
+long long
+foo (int d)
+{
+  d >>= a != (unsigned long long) -a;
+  return a + b;
+}

	Jakub


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] arm: Fix ICE caused by arm_gen_discompare_reg [PR94292]
  2020-03-25  7:21 [PATCH] arm: Fix ICE caused by arm_gen_discompare_reg [PR94292] Jakub Jelinek
@ 2020-03-25 17:51 ` Richard Earnshaw (lists)
  0 siblings, 0 replies; 2+ messages in thread
From: Richard Earnshaw (lists) @ 2020-03-25 17:51 UTC (permalink / raw)
  To: Jakub Jelinek, Ramana Radhakrishnan, Kyrylo Tkachov; +Cc: gcc-patches

On 25/03/2020 07:21, Jakub Jelinek via Gcc-patches wrote:
> Hi!
> 
> The following testcase ICEs, because arm_gen_discompare_reg creates invalid
> RTL which then propagates into DEBUG_INSNs and ICEs while handling them.
> The problem is that this function emits
> (insn 18 17 19 2 (set (reg:CC_DNE 100 cc)
>         (compare (ior:SI (ne:SI (subreg:SI (reg:DI 129) 0)
>                     (subreg:SI (reg:DI 114 [ _2 ]) 0))
>                 (ne:SI (subreg:SI (reg:DI 129) 4)
>                     (subreg:SI (reg:DI 114 [ _2 ]) 4)))
>             (const_int 0 [0]))) "pr94292.c":7:11 325 {*cmp_ior}
>      (nil))
> and the invalid thing is that the COMPARE has VOIDmode.  Setting a
> non-VOIDmode SET_DEST to VOIDmode SET_SRC is only valid if the SET_SRC is
> CONST_INT/CONST_DOUBLE.
> The following patch fixes it by giving the COMPARE the same mode as it gives
> to the SET_DEST cc register.

Ooops!

> 
> Bootstrapped/regtested on armv7hl-linux-gnueabi, ok for trunk?
> 
> 2020-03-25  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR target/94292
> 	* config/arm/arm.c (arm_gen_discompare_reg): Set mode of COMPARE to
> 	mode rather than VOIDmode.
> 

It's arm_gen_dicompare_reg (no 's').  Similarly in the summary line and
elsewhere in the description.

> 	* gcc.dg/pr94292.c: New test.

Otherwise, OK.

R.

> 
> --- gcc/config/arm/arm.c.jj	2020-03-18 19:25:33.000000000 +0100
> +++ gcc/config/arm/arm.c	2020-03-24 13:14:38.568689174 +0100
> @@ -15763,7 +15763,7 @@ arm_gen_dicompare_reg (rtx_code code, rt
>  	cc_reg = gen_rtx_REG (mode, CC_REGNUM);
>  
>  	emit_insn (gen_rtx_SET (cc_reg,
> -				gen_rtx_COMPARE (VOIDmode, conjunction,
> +				gen_rtx_COMPARE (mode, conjunction,
>  						 const0_rtx)));
>  	return cc_reg;
>        }
> --- gcc/testsuite/gcc.dg/pr94292.c.jj	2020-03-24 13:07:12.694449518 +0100
> +++ gcc/testsuite/gcc.dg/pr94292.c	2020-03-24 13:06:53.720737198 +0100
> @@ -0,0 +1,13 @@
> +/* PR target/94292 */
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -g -fno-tree-dce" } */
> +
> +unsigned short a;
> +unsigned long long b;
> +
> +long long
> +foo (int d)
> +{
> +  d >>= a != (unsigned long long) -a;
> +  return a + b;
> +}
> 
> 	Jakub
> 


^ permalink raw reply	[flat|nested] 2+ messages in thread

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