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[CFIInserter] Turn a reachable llvm_unreachable into a report_fatal_error. #168777

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Merged
merged 2 commits into from
Nov 20, 2025
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[CFIInserter] Turn a reachable llvm_unreachable into a report_fatal_error. #168777

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efee3ec
[CFIInsert] Turn a reachable llvm_unreachable into a report_fatal_error.
topperc Nov 19, 2025
3491b46
fixup! Use reportFatalInternalError
topperc Nov 20, 2025
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3 changes: 2 additions & 1 deletion llvm/lib/CodeGen/CFIInstrInserter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -272,7 +272,8 @@ void CFIInstrInserter::calculateOutgoingCFAInfo(MBBCFAInfo &MBBInfo) {
CSRLocMap.insert(
{CFI.getRegister(), CSRSavedLocation(CSRReg, CSROffset)});
} else if (It->second.Reg != CSRReg || It->second.Offset != CSROffset) {
llvm_unreachable("Different saved locations for the same CSR");
reportFatalInternalError(
"Different saved locations for the same CSR");
}
CSRSaved.set(CFI.getRegister());
}
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7 changes: 4 additions & 3 deletions llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir
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@@ -1,7 +1,8 @@
# RUN: llc -x mir < %s -mtriple=riscv64 \
# RUN: not --crash llc %s -mtriple=riscv64 \
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@mikaelholmen mikaelholmen Nov 20, 2025

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With this change llc will now open cfi-multiple-locations.s for writing in the local directory (which may be write protected). Can we add back the "-x mir < " or add "-o -" or something to avoid this?

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@mgudim mgudim Nov 20, 2025

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https://github.com/llvm/llvm-project/pull/168865/files

# RUN: -run-pass=cfi-instr-inserter \
# RUN: -riscv-enable-cfi-instr-inserter=true
# UNSUPPORTED: target={{.*}}
# RUN: -riscv-enable-cfi-instr-inserter=true 2>&1 | FileCheck %s

# CHECK: LLVM ERROR: Different saved locations for the same CSR

# Technically, it is possible that a callee-saved register is saved in multiple different locations.
# CFIInstrInserter should handle this, but currently it does not.
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4 changes: 1 addition & 3 deletions llvm/test/CodeGen/X86/cfi-inserter-verify-inconsistent-loc.mir
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@@ -1,4 +1,3 @@
# REQUIRES: asserts
# RUN: not --crash llc -o - %s -mtriple=x86_64-- \
# RUN: -run-pass=cfi-instr-inserter 2>&1 | FileCheck %s
# Test that CSR being saved in multiple locations can be caught by
Expand All @@ -10,8 +9,7 @@
}
...
---
# CHECK: Different saved locations for the same CSR
# CHECK-NEXT: UNREACHABLE executed
# CHECK: LLVM ERROR: Different saved locations for the same CSR
name: inconsistentlocs
body: |
bb.0:
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