[PATCH] Check SCALAR_INT_MODE_P in try_const_anchors

[Jiufu Guo <guojiufu@linux.ibm.com>]

Hi,

The const_anchor in cse.cc supports integer constants only.
There is a "gcc_assert (SCALAR_INT_MODE_P (mode))" in
try_const_anchors.

In the latest code, some non-integer modes are used with const int.
For examples:
"set (mem/c:BLK (xx) (const_int 0 [0])" occur in md files of
rs6000, i386, arm, and pa. For this, the mode may be BLKmode.
Pattern "(set (strict_low_part (xx)) (const_int xx))" could
be generated in a few ports. For this, the mode may be VOIDmode.

So, avoid mode other than SCALAR_INT_MODE in try_const_anchors
would be needed.

Some discussions in the previous thread:
https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621097.html

Bootstrap &regtest pass on ppc64{,le} and x86_64.
Is this ok for trunk?


BR,
Jeff (Jiufu Guo)

gcc/ChangeLog:

	* cse.cc (try_const_anchors): Check SCALAR_INT_MODE.

---
 gcc/cse.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/gcc/cse.cc b/gcc/cse.cc
index 2bb63ac4105..ddb76fd281d 100644
--- a/gcc/cse.cc
+++ b/gcc/cse.cc
@@ -1312,11 +1312,10 @@ try_const_anchors (rtx src_const, machine_mode mode)
   rtx lower_exp = NULL_RTX, upper_exp = NULL_RTX;
   unsigned lower_old, upper_old;
 
-  /* CONST_INT is used for CC modes, but we should leave those alone.  */
-  if (GET_MODE_CLASS (mode) == MODE_CC)
+  /* CONST_INT may be in various modes, avoid non-scalar-int mode. */
+  if (!SCALAR_INT_MODE_P (mode))
     return NULL_RTX;
 
-  gcc_assert (SCALAR_INT_MODE_P (mode));
   if (!compute_const_anchors (src_const, &lower_base, &lower_offs,
 			      &upper_base, &upper_offs))
     return NULL_RTX;
-- 
2.39.3