Reviewer feedback

Author: dakersnar

llvm/lib/Transforms/Scalar/InferAlignment.cpp

@@ -35,22 +35,23 @@ static bool tryToPropagateAlign(Function &F, const DataLayout &DL) {
     for (Instruction &I : BB) {
       if (auto *PtrOp = getLoadStorePointerOperand(&I)) {
         Align LoadStoreAlign = getLoadStoreAlignment(&I);
-        APInt OffsetFromBase = APInt(
-            DL.getIndexSizeInBits(PtrOp->getType()->getPointerAddressSpace()),
-            0);
-        PtrOp = PtrOp->stripAndAccumulateInBoundsConstantOffsets(
-            DL, OffsetFromBase);
+        APInt OffsetFromBase =
+            APInt(DL.getIndexTypeSizeInBits(PtrOp->getType()), 0);
+        PtrOp = PtrOp->stripAndAccumulateConstantOffsets(DL, OffsetFromBase, true);
         Align BasePointerAlign =
             commonAlignment(LoadStoreAlign, OffsetFromBase.getLimitedValue());
 
-        if (BestBasePointerAligns.count(PtrOp) &&
-            BestBasePointerAligns[PtrOp] > BasePointerAlign) {
-          Align BetterLoadStoreAlign = commonAlignment(
-              BestBasePointerAligns[PtrOp], OffsetFromBase.getLimitedValue());
-          setLoadStoreAlignment(&I, BetterLoadStoreAlign);
-          Changed = true;
-        } else {
-          BestBasePointerAligns[PtrOp] = BasePointerAlign;
+        auto [It, Inserted] =
+            BestBasePointerAligns.try_emplace(PtrOp, BasePointerAlign);
+        if (!Inserted) {
+          if (It->second > BasePointerAlign) {
+            Align BetterLoadStoreAlign =
+                commonAlignment(It->second, OffsetFromBase.getLimitedValue());
+            setLoadStoreAlignment(&I, BetterLoadStoreAlign);
+            Changed = true;
+          } else {
+            It->second = BasePointerAlign;
+          }
         }
       }
     }

llvm/test/Transforms/InferAlignment/propagate-from-other-load-stores.ll

@@ -8,10 +8,9 @@
 ; Test that we can propagate the align 16 to the load and store that are set to align 4
 ; ------------------------------------------------------------------------------
 
-; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite)
-define void @prop_align(ptr noundef readonly captures(none) %v, ptr noundef writeonly captures(none) initializes((0, 32)) %vout) local_unnamed_addr #0 {
+define void @prop_align(ptr %v, ptr %vout) {
 ; CHECK-LABEL: define void @prop_align(
-; CHECK-SAME: ptr noundef readonly captures(none) [[V:%.*]], ptr noundef writeonly captures(none) initializes((0, 32)) [[VOUT:%.*]]) local_unnamed_addr {
+; CHECK-SAME: ptr [[V:%.*]], ptr [[VOUT:%.*]]) {
 ; CHECK-NEXT:    [[DOTUNPACK_UNPACK:%.*]] = load float, ptr [[V]], align 16
 ; CHECK-NEXT:    [[DOTUNPACK_ELT7:%.*]] = getelementptr inbounds nuw i8, ptr [[V]], i64 4
 ; CHECK-NEXT:    [[DOTUNPACK_UNPACK8:%.*]] = load float, ptr [[DOTUNPACK_ELT7]], align 4
@@ -81,10 +80,9 @@ define void @prop_align(ptr noundef readonly captures(none) %v, ptr noundef writ
 ; Test that alignment is not propagated from a source that does not dominate the destination
 ; ------------------------------------------------------------------------------
 
-; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: readwrite)
-define void @no_prop_align(ptr noundef readonly captures(none) %v, ptr noundef writeonly captures(none) initializes((0, 32)) %vout, i1 %cond) local_unnamed_addr #0 {
+define void @no_prop_align(ptr %v, ptr %vout, i1 %cond) {
 ; CHECK-LABEL: define void @no_prop_align(
-; CHECK-SAME: ptr noundef readonly captures(none) [[V:%.*]], ptr noundef writeonly captures(none) initializes((0, 32)) [[VOUT:%.*]], i1 [[COND:%.*]]) local_unnamed_addr {
+; CHECK-SAME: ptr [[V:%.*]], ptr [[VOUT:%.*]], i1 [[COND:%.*]]) {
 ; CHECK-NEXT:    br i1 [[COND]], label %[[BRANCH1:.*]], label %[[BRANCH2:.*]]
 ; CHECK:       [[BRANCH1]]:
 ; CHECK-NEXT:    [[DOTUNPACK_UNPACK:%.*]] = load float, ptr [[V]], align 16