So combine (rightfully) produces:
(subreg:DD (vec_concat:V2DI (const_int -1 [0xffffffffffffffff])
(reg:DI 145 [ _22 ])) 0)
And then calls simplify_subreg on it.
simplify_subreg then sees it can remove the vec_concat as this is
the lower part and try to do `(subreg:DD (const_int -1 [0xffffffffffffffff]))`
but that is an invalid constant for DF64 so simplify_subreg rejects
that and returns NULL but there is code in simplify_subreg to create
a SUBREG then if the subreg validates. The problem is we are using DImode
for the inner mode and that validates but when gen_rtx_SUBREG is called
the inner mode of DImode is not there; only VOIDmode.
So the fix is to check for VOIDmode before the call to validate_subreg.
Bootstrapped and tested on x86_64-linux-gnu. And lightly tested for
aarch64-linux-gnu.
PR rtl-optimization/123822
gcc/ChangeLog:
* simplify-rtx.cc (simplify_context::simplify_subreg): Check the
mode of the part to be non-VOIDmode before calling gen_rtx_SUBREG.
gcc/testsuite/ChangeLog:
* gcc.dg/torture/pr123822-1.c: New test.
Signed-off-by: Andrew Pinski <[email protected]>
(cherry picked from commit 794acc6340cb2869a74fc69104c38ac5c2840a91)
---
gcc/simplify-rtx.cc | 3 ++-
gcc/testsuite/gcc.dg/torture/pr123822-1.c | 16 ++++++++++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr123822-1.c
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index f8c12d64f0b..5a520cccf3f 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8184,7 +8184,8 @@ simplify_context::simplify_subreg (machine_mode
outermode, rtx op,
res = simplify_subreg (outermode, part, part_mode, final_offset);
if (res)
return res;
- if (validate_subreg (outermode, part_mode, part, final_offset))
+ if (GET_MODE (part) != VOIDmode
+ && validate_subreg (outermode, part_mode, part, final_offset))
return gen_rtx_SUBREG (outermode, part, final_offset);
return NULL_RTX;
}
diff --git a/gcc/testsuite/gcc.dg/torture/pr123822-1.c
b/gcc/testsuite/gcc.dg/torture/pr123822-1.c
new file mode 100644
index 00000000000..38dd05507d1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr123822-1.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ffast-math" } */
+/* { dg-require-effective-target dfp } */
+
+/* PR rtl-optimization/123822 */
+
+typedef __attribute__((__vector_size__(16))) _Decimal64 D;
+
+int i;
+D d;
+
+void
+foo()
+{
+ d /= (D)(d >= *(D *)__builtin_memset(&d, i, 3));
+}
--
2.43.0
