https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127771
Bug ID: 127771
Summary: [17 Regression] ICE in execute_todo, at passes.cc:2147
since r17-4816
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: dhruvc at gcc dot gnu.org
Reporter: dhruvc at gcc dot gnu.org
CC: karmea01 at gcc dot gnu.org
Target Milestone: ---
Target: aarch64
r17-4816-gb24418a2212866 introduces a temporary LHS for an intrinsic call whose
result is discarded. It uses create_tmp_var (generating a VAR_DECL) which sets
ssa_renaming_needed. The consequent passes that fold do not request
TODO_update_ssa, so execute_todo asserts.
This needs the fold to run after SSA construction. In the testcase the second
operand is not yet a constant when intrinsics are first folded from gimple-low,
so the fold declines there and only succeeds once CCP has propagated the splat.
This happens in C only as the C++ front end deletes the discarded call while
parsing, so the folder never runs.
Min-repro:
===
#include <arm_sve.h>
void g (svbool_t p, svuint32_t a, int k)
{
svmul_x (p, a, svdup_u32 (k ? 1 : 1));
}
===
Compile flags: -march=armv8.2-a+sve -O1
Error:
===
during GIMPLE pass: ccp
<source>: In function 'g':
<source>:6:1: internal compiler error: in execute_todo, at passes.cc:2147
6 | }
| ^
===
Compiler explorer: https://godbolt.org/z/dj597jz4h
