https://gcc.gnu.org/g:06221fe413302f16bbbc22324f98173f45ea9088
commit r16-7558-g06221fe413302f16bbbc22324f98173f45ea9088 Author: Richard Earnshaw <[email protected]> Date: Tue Feb 17 16:19:32 2026 +0000 arm: don't allow movMcc when short-it but no vsel [PR124134] Perverse combinations of options can lead to the compiler having to work around unexpected situations. Armv8 originally specified that complex IT sequences were deprecated for performance (it was later rescinded). If the options restrict the floating-point unit to one without vsel, then movMcc patterns need complex IT sequences and we can end up with unmatched RTL patterns. Avoid this by failing early when the target patterns are disabled. gcc/ChangeLog: PR target/124134 * config/arm/arm.md (movsfcc): FAIL if using restricted IT blocks and we lack VSEL. (movdfcc): Likewise. gcc/testsuite/ChangeLog: PR target/124134 * gcc.target/arm/pr124134.c: New test. Diff: --- gcc/config/arm/arm.md | 12 ++++++++++-- gcc/testsuite/gcc.target/arm/pr124134.c | 10 ++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md index 4c3f1a5e2af8..a3e6a362fdef 100644 --- a/gcc/config/arm/arm.md +++ b/gcc/config/arm/arm.md @@ -8374,9 +8374,13 @@ enum rtx_code code = GET_CODE (operands[1]); rtx ccreg; + /* Perverse combinations of architecture options can't be supported + as they need conditional instructions. */ + if (TARGET_THUMB2 && arm_restrict_it && !TARGET_VFP5) + FAIL; if (!arm_validize_comparison (&operands[1], &XEXP (operands[1], 0), &XEXP (operands[1], 1))) - FAIL; + FAIL; code = GET_CODE (operands[1]); ccreg = arm_gen_compare_reg (code, XEXP (operands[1], 0), @@ -8396,9 +8400,13 @@ enum rtx_code code = GET_CODE (operands[1]); rtx ccreg; + /* Perverse combinations of architecture options can't be supported + as they need conditional instructions. */ + if (TARGET_THUMB2 && arm_restrict_it && !TARGET_VFP5) + FAIL; if (!arm_validize_comparison (&operands[1], &XEXP (operands[1], 0), &XEXP (operands[1], 1))) - FAIL; + FAIL; code = GET_CODE (operands[1]); ccreg = arm_gen_compare_reg (code, XEXP (operands[1], 0), XEXP (operands[1], 1), NULL_RTX); diff --git a/gcc/testsuite/gcc.target/arm/pr124134.c b/gcc/testsuite/gcc.target/arm/pr124134.c new file mode 100644 index 000000000000..9d80f95aff9b --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/pr124134.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target arm_arch_v7a_fp_hard_ok } */ +/* { dg-add-options arm_arch_v7a_fp_hard } */ +/* { dg-additional-options "-O2 -mrestrict-it" } */ +double max___a, max___b; +double max() { + if (max___a < max___b) + return max___b; + return max___a; +}
