vendor/llvm-project/llvmorg-14-init-17616-g024a1fab5c35

1 files changed, 10 insertions, 11 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 4dc712f32536..71a5ae24eead 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -800,22 +800,21 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
         // Round NTZ down to the next byte.  If we have 11 trailing zeros, then
         // we need all the bits down to bit 8.  Likewise, round NLZ.  If we
         // have 14 leading zeros, round to 8.
-        NLZ &= ~7;
-        NTZ &= ~7;
+        NLZ = alignDown(NLZ, 8);
+        NTZ = alignDown(NTZ, 8);
         // If we need exactly one byte, we can do this transformation.
-        if (BitWidth-NLZ-NTZ == 8) {
-          unsigned ResultBit = NTZ;
-          unsigned InputBit = BitWidth-NTZ-8;
-
+        if (BitWidth - NLZ - NTZ == 8) {
           // Replace this with either a left or right shift to get the byte into
           // the right place.
           Instruction *NewVal;
-          if (InputBit > ResultBit)
-            NewVal = BinaryOperator::CreateLShr(II->getArgOperand(0),
-                    ConstantInt::get(I->getType(), InputBit-ResultBit));
+          if (NLZ > NTZ)
+            NewVal = BinaryOperator::CreateLShr(
+                II->getArgOperand(0),
+                ConstantInt::get(I->getType(), NLZ - NTZ));
           else
-            NewVal = BinaryOperator::CreateShl(II->getArgOperand(0),
-                    ConstantInt::get(I->getType(), ResultBit-InputBit));
+            NewVal = BinaryOperator::CreateShl(
+                II->getArgOperand(0),
+                ConstantInt::get(I->getType(), NTZ - NLZ));
           NewVal->takeName(I);
           return InsertNewInstWith(NewVal, *I);
         }