https://gcc.gnu.org/g:8d0676db179aa31207bc4dd29e1c310823988f4b
commit r17-3140-g8d0676db179aa31207bc4dd29e1c310823988f4b Author: Jakub Jelinek <[email protected]> Date: Fri Aug 7 17:33:53 2026 +0200 s390: Fix ICE in usubc5 [PR126667] The following testcase ICEs on s390x-linux I believe since r15-6791 when usubc<mode>5 named pattern has been introduced. It intentionally uses general_operand predicate for operands[4], so that it can test it against const0_rtx and handle that differently, but otherwise it uses xor<mode>3 insn with operands[4] as first input, which has nonimmediate_operand. So we emit (xor:DI (const1_rtx) (const1_rtx)) and then fail to recognize it. The following patch just forces it into a register in that case, cse or combine can then simplify it. The other option would be to check for CONSTANT_P, force into REG unless it is CONST_INT and if it is CONST_INT, perform the xor at compile time, but then the compare too and unsure what to pass to the subsequent insn. The testcase is simplified from a larger botan real-world testcase (though there isn't usubc with a constant 1 carry in visible in the source). 2026-08-07 Jakub Jelinek <[email protected]> PR target/126667 * config/s390/s390.md (usubc<mode>5): If operands[4] is an immediate operand other than const0_rtx, force it into reg before using it in xor<mode>3 insn. * gcc.dg/pr126667.c: New test. * gcc.target/s390/pr126667.c: New test. Reviewed-by: Andreas Krebbel <[email protected]> Diff: --- gcc/config/s390/s390.md | 4 +++- gcc/testsuite/gcc.dg/pr126667.c | 9 +++++++++ gcc/testsuite/gcc.target/s390/pr126667.c | 9 +++++++++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md index 587077b84fa6..aa9b011278db 100644 --- a/gcc/config/s390/s390.md +++ b/gcc/config/s390/s390.md @@ -6745,7 +6745,9 @@ else { rtx tmp = gen_reg_rtx (<MODE>mode); - emit_insn (gen_xor<mode>3 (tmp, operands[4], const1_rtx)); + emit_insn (gen_xor<mode>3 (tmp, CONSTANT_P (operands[4]) + ? force_reg (<MODE>mode, operands[4]) + : operands[4], const1_rtx)); rtx slb_cond = s390_emit_compare (<MODE>mode, LEU, tmp, const0_rtx); emit_insn (gen_sub<mode>3_slb_borrow1_cc (operands[0], operands[2], operands[3], slb_cond)); } diff --git a/gcc/testsuite/gcc.dg/pr126667.c b/gcc/testsuite/gcc.dg/pr126667.c new file mode 100644 index 000000000000..f9e4a2120add --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr126667.c @@ -0,0 +1,9 @@ +/* PR target/126667 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +unsigned long +foo (unsigned long x, unsigned long y, unsigned long *p) +{ + return __builtin_subcl (x, y, 1UL, p); +} diff --git a/gcc/testsuite/gcc.target/s390/pr126667.c b/gcc/testsuite/gcc.target/s390/pr126667.c new file mode 100644 index 000000000000..0e6cd1467a2c --- /dev/null +++ b/gcc/testsuite/gcc.target/s390/pr126667.c @@ -0,0 +1,9 @@ +/* PR target/126667 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=z14" } */ + +unsigned long +foo (unsigned long x, unsigned long y, unsigned long *p) +{ + return __builtin_subcl (x, y, 1UL, p); +}
