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[IR][AutoUpgrade] Drop align attribute from void return types

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Since D87304, `align` become an invalid attribute on none pointer types and
verifier will reject bitcode that has invalid `align` attribute.

The problem is before the change, DeadArgumentElimination can easily
turn a pointer return type into a void return type without removing
`align` attribute. Teach Autograde to remove invalid `align` attribute
from return types to maintain bitcode compatibility.

rdar://77022993

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D102201
This commit is contained in:
Steven Wu
2021-05-11 08:23:08 -07:00
parent d6a228cba4
commit 4eff946947
4 changed files with 27 additions and 1 deletions
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8
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
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@@ -5562,8 +5562,8 @@ Error BitcodeReader::materialize(GlobalValue *GV) {
}
}
// "Upgrade" older incorrect branch weights by dropping them.
for (auto &I : instructions(F)) {
// "Upgrade" older incorrect branch weights by dropping them.
if (auto *MD = I.getMetadata(LLVMContext::MD_prof)) {
if (MD->getOperand(0) != nullptr && isa<MDString>(MD->getOperand(0))) {
MDString *MDS = cast<MDString>(MD->getOperand(0));
@@ -5590,6 +5590,12 @@ Error BitcodeReader::materialize(GlobalValue *GV) {
I.setMetadata(LLVMContext::MD_prof, nullptr);
}
}
// Remove align from return attribute on CallInst.
if (auto *CI = dyn_cast<CallInst>(&I)) {
if (CI->getFunctionType()->getReturnType()->isVoidTy())
CI->removeAttribute(0, Attribute::Alignment);
}
}
// Look for functions that rely on old function attribute behavior.