On 6/21/24 8:46 AM, Artemiy Volkov wrote:
Presently, the code fragment:
int x[5];
void
d(int a, int b, int c) {
for (int i = 0; i < 5; i++)
x[i] = (a != b) ? c : a;
}
causes an ICE when compiled with -O2 -march=rv32i_zicond:
test.c: In function 'd':
test.c: error: unrecognizable insn:
11 | }
| ^
(insn 8 5 9 2 (set (reg:SI 139 [ iftmp.0_2 ])
(if_then_else:SI (ne:SI (reg/v:SI 136 [ a ])
(reg/v:SI 137 [ b ]))
(reg/v:SI 136 [ a ])
(reg/v:SI 138 [ c ]))) -1
(nil))
during RTL pass: vregs
This happens because, as part of one of the optimizations in
riscv_expand_conditional_move(), an if_then_else is generated with both
comparands being register operands, resulting in an unmatchable insn since
Zicond patterns require constant 0 as the second comparand. Fix this by adding
a extra check before performing this optimization.
The code snippet mentioned above is also included in this patch as a new Zicond
testcase.
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_expand_conditional_move): Add a
CONST0_RTX check.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/zicond-ice-3.c: New test.
I've pushed this to the trunk. Thanks Artemiy!
Jeff
