[PATCH] D158304: [RISCV] Fix a UBSAN failure for passing INT64_MIN to std::abs.
Craig Topper via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 18 12:48:02 PDT 2023
This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG078eb4bd85dd: [RISCV] Fix a UBSAN failure for passing INT64_MIN to std::abs. (authored by craig.topper).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D158304/new/
https://reviews.llvm.org/D158304
Files:
llvm/lib/Target/RISCV/RISCVISelLowering.cpp
Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -3232,12 +3232,13 @@
bool Negate = false;
int64_t SplatStepVal = StepNumerator;
unsigned StepOpcode = ISD::MUL;
- if (StepNumerator != 1) {
- if (isPowerOf2_64(std::abs(StepNumerator))) {
- Negate = StepNumerator < 0;
- StepOpcode = ISD::SHL;
- SplatStepVal = Log2_64(std::abs(StepNumerator));
- }
+ // Exclude INT64_MIN to avoid passing it to std::abs. We won't optimize it
+ // anyway as the shift of 63 won't fit in uimm5.
+ if (StepNumerator != 1 && StepNumerator != INT64_MIN &&
+ isPowerOf2_64(std::abs(StepNumerator))) {
+ Negate = StepNumerator < 0;
+ StepOpcode = ISD::SHL;
+ SplatStepVal = Log2_64(std::abs(StepNumerator));
}
// Only emit VIDs with suitably-small steps/addends. We use imm5 is a
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