Hi!
The following testcase ICEs on aarch64. The problem is that
op0 is (subreg:HI (reg:HF ...) 0) and because we can't create a SUBREG of a
SUBREG and aarch64 doesn't have HImode insv, only SImode insv,
store_bit_field_using_insv tries to create (subreg:SI (reg:HF ...) 0)
which is not valid for the target and so gen_rtx_SUBREG ICEs.
The following patch fixes it by punting if the to be created SUBREG
doesn't validate, callers of store_bit_field_using_insv can handle
the fallback.
Bootstrapped/regtested on x86_64-linux, i686-linux and aarch64-linux, ok for
trunk?
2021-03-03 Jakub Jelinek <ja...@redhat.com>
PR middle-end/93235
* expmed.c (store_bit_field_using_insv): Return false of xop0 is a
SUBREG and a SUBREG to op_mode can't be created.
* gcc.target/aarch64/pr93235.c: New test.
--- gcc/expmed.c.jj 2021-01-04 10:25:39.761223316 +0100
+++ gcc/expmed.c 2021-03-03 19:22:41.249301351 +0100
@@ -629,9 +629,16 @@ store_bit_field_using_insv (const extrac
/* If xop0 is a register, we need it in OP_MODE
to make it acceptable to the format of insv. */
if (GET_CODE (xop0) == SUBREG)
- /* We can't just change the mode, because this might clobber op0,
- and we will need the original value of op0 if insv fails. */
- xop0 = gen_rtx_SUBREG (op_mode, SUBREG_REG (xop0), SUBREG_BYTE (xop0));
+ {
+ /* If such a SUBREG can't be created, give up. */
+ if (!validate_subreg (op_mode, GET_MODE (SUBREG_REG (xop0)),
+ SUBREG_REG (xop0), SUBREG_BYTE (xop0)))
+ return false;
+ /* We can't just change the mode, because this might clobber op0,
+ and we will need the original value of op0 if insv fails. */
+ xop0 = gen_rtx_SUBREG (op_mode, SUBREG_REG (xop0),
+ SUBREG_BYTE (xop0));
+ }
if (REG_P (xop0) && GET_MODE (xop0) != op_mode)
xop0 = gen_lowpart_SUBREG (op_mode, xop0);
}
--- gcc/testsuite/gcc.target/aarch64/pr93235.c.jj 2021-03-03
19:28:47.743300618 +0100
+++ gcc/testsuite/gcc.target/aarch64/pr93235.c 2021-03-03 19:28:27.247524328
+0100
@@ -0,0 +1,12 @@
+/* PR middle-end/93235 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-strict-aliasing" } */
+
+struct sfp16 { __fp16 f; };
+struct sfp16
+foo (short x)
+{
+ struct sfp16 a;
+ *(short*)&a.f = x;
+ return a;
+}
Jakub
