[committed] arc: Fail conditional move expand patterns

[committed] arc: Fail conditional move expand patterns

[Claudiu Zissulescu]

If the movcc comparison is not valid it triggers an assert in the
current implementation.  This behavior is not needed as we can FAIL
the movcc expand pattern.

gcc/
	* config/arc/arc.cc (gen_compare_reg): Return NULL_RTX if the
	comparison is not valid.
	* config/arc/arc.md (movsicc): Fail if comparison is not valid.
	(movdicc): Likewise.
	(movsfcc): Likewise.
	(movdfcc): Likewise.

Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>
---
 gcc/config/arc/arc.cc |  3 ++-
 gcc/config/arc/arc.md | 25 ++++++++++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/gcc/config/arc/arc.cc b/gcc/config/arc/arc.cc
index 8cc173519ab..c27ba99eb60 100644
--- a/gcc/config/arc/arc.cc
+++ b/gcc/config/arc/arc.cc
@@ -2256,7 +2256,8 @@ gen_compare_reg (rtx comparison, machine_mode omode)
   cmode = GET_MODE (x);
   if (cmode == VOIDmode)
     cmode = GET_MODE (y);
-  gcc_assert (cmode == SImode || cmode == SFmode || cmode == DFmode);
+  if (cmode != SImode && cmode != SFmode && cmode != DFmode)
+    return NULL_RTX;
   if (cmode == SImode)
     {
       if (!register_operand (x, SImode))
diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md
index ace3cb70424..39b358052c1 100644
--- a/gcc/config/arc/arc.md
+++ b/gcc/config/arc/arc.md
@@ -1618,8 +1618,11 @@ (define_expand "movsicc"
 		         (match_operand:SI 2 "nonmemory_operand" "")
  		         (match_operand:SI 3 "register_operand" "")))]
   ""
-  "operands[1] = gen_compare_reg (operands[1], VOIDmode);")
-
+  "
+  operands[1] = gen_compare_reg (operands[1], VOIDmode);
+  if (operands[1] == NULL_RTX)
+    FAIL;
+  ")
 
 (define_expand "movdicc"
   [(set (match_operand:DI 0 "dest_reg_operand" "")
@@ -1627,7 +1630,11 @@ (define_expand "movdicc"
 		        (match_operand:DI 2 "nonmemory_operand" "")
 		        (match_operand:DI 3 "register_operand" "")))]
   ""
-  "operands[1] = gen_compare_reg (operands[1], VOIDmode);")
+  "
+  operands[1] = gen_compare_reg (operands[1], VOIDmode);
+  if (operands[1] == NULL_RTX)
+    FAIL;
+  ")
 
 
 (define_expand "movsfcc"
@@ -1636,7 +1643,11 @@ (define_expand "movsfcc"
 		      (match_operand:SF 2 "nonmemory_operand" "")
 		      (match_operand:SF 3 "register_operand" "")))]
   ""
-  "operands[1] = gen_compare_reg (operands[1], VOIDmode);")
+  "
+  operands[1] = gen_compare_reg (operands[1], VOIDmode);
+  if (operands[1] == NULL_RTX)
+    FAIL;
+  ")
 
 (define_expand "movdfcc"
   [(set (match_operand:DF 0 "dest_reg_operand" "")
@@ -1644,7 +1655,11 @@ (define_expand "movdfcc"
 		      (match_operand:DF 2 "nonmemory_operand" "")
 		      (match_operand:DF 3 "register_operand" "")))]
   ""
-  "operands[1] = gen_compare_reg (operands[1], VOIDmode);")
+  "
+  operands[1] = gen_compare_reg (operands[1], VOIDmode);
+  if (operands[1] == NULL_RTX)
+    FAIL;
+  ")
 
 (define_insn "*movsicc_insn"
   [(set (match_operand:SI 0 "dest_reg_operand" "=w,w")
-- 
2.35.1

Re: [committed] arc: Fail conditional move expand patterns

[Robin Dapp]

> If the movcc comparison is not valid it triggers an assert in the
> current implementation.  This behavior is not needed as we can FAIL
> the movcc expand pattern.

In case of a MODE_CC comparison you can also just return it as described
here https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104154

or here: https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590639.html

If there already is a "CC comparison" the backend does not need to
create one and ifcvt can make use of this, creating better sequences.

Regards
 Robin

Re: [committed] arc: Fail conditional move expand patterns

[Claudiu Zissulescu Ianculescu]

Hi Robin,

I don't know how I missed your arc related patch, I'll bootstrap and test
your patch asap.

Thanks,
Claudiu


On Fri, Feb 25, 2022 at 3:29 PM Robin Dapp <rdapp@linux.ibm.com> wrote:

> > If the movcc comparison is not valid it triggers an assert in the
> > current implementation.  This behavior is not needed as we can FAIL
> > the movcc expand pattern.
>
> In case of a MODE_CC comparison you can also just return it as described
> here https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104154
>
> or here:
> https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590639.html
>
> If there already is a "CC comparison" the backend does not need to
> create one and ifcvt can make use of this, creating better sequences.
>
> Regards
>  Robin
>