simplify_gen_subreg rejected subregs of literal constants if
MODE_COMPOSITE_P. This was added by the fix for PR96648 in
g:c0f772894b6b3cd8ed5c5dd09d0c7917f51cf70f. Jakub said:
As for the simplify_gen_subreg change, I think it would be desirable
to just avoid creating SUBREGs of constants on all targets and for all
constants, if simplify_immed_subreg simplified, fine, otherwise punt,
but as we are late in GCC11 development, the patch instead guards this
behavior on MODE_COMPOSITE_P (outermode) - i.e. only conversions to
powerpc{,64,64le} double double long double - and only for the cases where
simplify_immed_subreg was called.
I'm not sure about relaxing the codes further, since subregs might
be wanted for CONST, SYMBOL_REF and LABEL_REF. But removing the
MODE_COMPOSITE_P is needed to fix PR120718, where we get an ICE
from generating a subreg of a V2SI const_vector.
Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
Richard
gcc/
PR rtl-optimization/120718
* simplify-rtx.cc (simplify_context::simplify_gen_subreg):
Remove MODE_COMPOSITE_P condition.
gcc/testsuite/
PR rtl-optimization/120718
* gcc.target/aarch64/sve/acle/general/pr120718.c: New test.
---
gcc/simplify-rtx.cc | 12 ++++--------
.../gcc.target/aarch64/sve/acle/general/pr120718.c | 12 ++++++++++++
2 files changed, 16 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr120718.c
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 8ef96b4c1c8..35070c09aa0 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8502,14 +8502,10 @@ simplify_context::simplify_gen_subreg (machine_mode
outermode, rtx op,
if (GET_CODE (op) == SUBREG
|| GET_CODE (op) == CONCAT
- || GET_MODE (op) == VOIDmode)
- return NULL_RTX;
-
- if (MODE_COMPOSITE_P (outermode)
- && (CONST_SCALAR_INT_P (op)
- || CONST_DOUBLE_AS_FLOAT_P (op)
- || CONST_FIXED_P (op)
- || GET_CODE (op) == CONST_VECTOR))
+ || CONST_SCALAR_INT_P (op)
+ || CONST_DOUBLE_AS_FLOAT_P (op)
+ || CONST_FIXED_P (op)
+ || GET_CODE (op) == CONST_VECTOR)
return NULL_RTX;
if (validate_subreg (outermode, innermode, op, byte))
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr120718.c
b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr120718.c
new file mode 100644
index 00000000000..9ca0938e36b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr120718.c
@@ -0,0 +1,12 @@
+/* { dg-options "-O2" } */
+
+#include <arm_sve.h>
+typedef int __attribute__((vector_size(8))) v2si;
+typedef struct { int x; int y; } A;
+void bar(A a);
+void foo()
+{
+ A a;
+ *(v2si *)&a = (v2si){0, (int)svcntd_pat(SV_ALL)};
+ bar(a);
+}
--
2.43.0
