[InstCombine] Remove redundant align 1 assumptions. #160695
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@llvm/pr-subscribers-llvm-transforms Author: Florian Hahn (fhahn) ChangesIt seems like we have a bunch of align 1 assumptions in practice and unless I am missing something they should not add any value. See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2861/files Full diff: https://github.com/llvm/llvm-project/pull/160695.diff 1 Files Affected:
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 6ad493772d170..896548ddd9931 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3412,6 +3412,9 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
!isPowerOf2_64(RK.ArgValue) || !isa<ConstantInt>(RK.IRArgValue))
continue;
+ if (RK.ArgValue == 1)
+ return CallBase::removeOperandBundle(II, OBU.getTagID());
+
// Don't try to remove align assumptions for pointers derived from
// arguments. We might lose information if the function gets inline and
// the align argument attribute disappears.
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It seems like we have a bunch of align 1 assumptions in practice and unless I am missing something they should not add any value. See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2861/files
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Woops stripped the update by accident. Should be back now |
nikic
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Sep 25, 2025
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| // Remove align 1 bundles; they don't add any useful information. | ||
| if (RK.ArgValue == 1) | ||
| return CallBase::removeOperandBundle(II, OBU.getTagID()); |
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Side note (as this is not the only place with this problem), but this API doesn't do the right thing if there are multiple assume operand bundles with the same name. No idea whether that's supposed to be allowed or only permitted by accident.
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It seems like we have a bunch of align 1 assumptions in practice and unless I am missing something they should not add any value. See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2861/files PR: llvm/llvm-project#160695
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It seems like we have a bunch of align 1 assumptions in practice and unless I am missing something they should not add any value. See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2861/files PR: llvm#160695
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It seems like we have a bunch of align 1 assumptions in practice and unless I am missing something they should not add any value.
See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2861/files