[llvm] [InstCombine] Remove redundant align 1 assumptions. (PR #160695)

[Nikita Popov via llvm-commits]

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@@ -3412,6 +3412,10 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
             !isPowerOf2_64(RK.ArgValue) || !isa<ConstantInt>(RK.IRArgValue))
           continue;
 
+        // 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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nikic wrote:

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.

https://github.com/llvm/llvm-project/pull/160695