https://gcc.gnu.org/g:5b865a03d8c85ee2d8aace0664c9685b2b477a28
commit 5b865a03d8c85ee2d8aace0664c9685b2b477a28 Author: Jeff Law <[email protected]> Date: Tue Dec 23 13:25:47 2025 -0700 [committed][RISC-V][PR target/123274] Add missing condition in usmul<mode>3 pattern As Andrew P. noted in the BZ, the expander is missing elements in its condition leading to generation of an insn that can't be matched. This adds the necessary condition to the usmul<mode>3 expander which in turn fixes the ICE. I just checked and that expander wansn't in gcc-15, so this is just a gcc-16 issue. Tested on riscv32-elf and riscv64-elf. I have a bootstrap in flight on the Pioneer, but I'm not expecting any surprises. Much like the patch earlier today, I'm going to push this now rather than wait for pre-commit CI. PR target/123274 gcc/ * config/riscv/riscv.md (usmul<mode>3): Add proper condition. gcc/testsuite/ * gcc.target/riscv/pr123274.c: New test. (cherry picked from commit 758876f023a58b9a02f350347b58d4e116a448bc) Diff: --- gcc/config/riscv/riscv.md | 2 +- gcc/testsuite/gcc.target/riscv/pr123274.c | 11 +++++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md index 6f8cd26e5c95..a24ec95b2e48 100644 --- a/gcc/config/riscv/riscv.md +++ b/gcc/config/riscv/riscv.md @@ -4727,7 +4727,7 @@ [(match_operand:ANYI 0 "register_operand") (match_operand:ANYI 1 "register_operand") (match_operand:ANYI 2 "register_operand")] - "" + "TARGET_ZMMUL || TARGET_MUL" { riscv_expand_usmul (operands[0], operands[1], operands[2]); DONE; diff --git a/gcc/testsuite/gcc.target/riscv/pr123274.c b/gcc/testsuite/gcc.target/riscv/pr123274.c new file mode 100644 index 000000000000..5f13e7c41fa6 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/pr123274.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=rv64id" { target rv64 } } */ +/* { dg-options "-O2 -march=rv32id" { target rv32 } } */ +unsigned a, b; + +void +foo() +{ + if (__builtin_mul_overflow(a, b, &b)) + b = 0xffffffff; +}
