[InstCombine] Propagate invariant.load metadata across unpacked loads

llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

@@ -737,6 +737,8 @@ static Instruction *unpackLoadToAggregate(InstCombinerImpl &IC, LoadInst &LI) {
       LoadInst *NewLoad = IC.combineLoadToNewType(LI, ST->getTypeAtIndex(0U),
                                                   ".unpack");
       NewLoad->setAAMetadata(LI.getAAMetadata());
+      // Copy invariant metadata from parent load.
+      NewLoad->copyMetadata(LI, LLVMContext::MD_invariant_load);
       return IC.replaceInstUsesWith(LI, IC.Builder.CreateInsertValue(
         PoisonValue::get(T), NewLoad, 0, Name));
     }
@@ -764,6 +766,8 @@ static Instruction *unpackLoadToAggregate(InstCombinerImpl &IC, LoadInst &LI) {
           Name + ".unpack");
       // Propagate AA metadata. It'll still be valid on the narrowed load.
       L->setAAMetadata(LI.getAAMetadata());
+      // Copy invariant metadata from parent load.
+      L->copyMetadata(LI, LLVMContext::MD_invariant_load);
       V = IC.Builder.CreateInsertValue(V, L, i);
     }
 

llvm/test/Transforms/InstCombine/invariant-metadata-propagation.ll

@@ -0,0 +1,46 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S < %s -passes=instcombine | FileCheck %s
+
+%struct.double2 = type { double, double }
+%struct.double1 = type { double }
+
+define %struct.double2 @func1(ptr addrspace(1) %a) {
+; CHECK-LABEL: define %struct.double2 @func1(
+; CHECK-SAME: ptr addrspace(1) [[A:%.*]]) {
+; CHECK-NEXT:    [[DOTUNPACK:%.*]] = load double, ptr addrspace(1) [[A]], align 16, !invariant.load [[META0:![0-9]+]]
+; CHECK-NEXT:    [[TMP1:%.*]] = insertvalue [[STRUCT_DOUBLE2:%.*]] poison, double [[DOTUNPACK]], 0
+; CHECK-NEXT:    [[DOTELT1:%.*]] = getelementptr inbounds nuw i8, ptr addrspace(1) [[A]], i64 8
+; CHECK-NEXT:    [[DOTUNPACK2:%.*]] = load double, ptr addrspace(1) [[DOTELT1]], align 8, !invariant.load [[META0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = insertvalue [[STRUCT_DOUBLE2]] [[TMP1]], double [[DOTUNPACK2]], 1
+; CHECK-NEXT:    ret [[STRUCT_DOUBLE2]] [[TMP2]]
+;
+  %1 = load %struct.double2, ptr addrspace(1) %a, align 16, !invariant.load !1
+  ret %struct.double2 %1
+}
+
+define %struct.double2 @func2(ptr %a) {
+; CHECK-LABEL: define %struct.double2 @func2(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT:    [[DOTUNPACK:%.*]] = load double, ptr [[A]], align 16, !invariant.load [[META0]]
+; CHECK-NEXT:    [[TMP1:%.*]] = insertvalue [[STRUCT_DOUBLE2:%.*]] poison, double [[DOTUNPACK]], 0
+; CHECK-NEXT:    [[DOTELT1:%.*]] = getelementptr inbounds nuw i8, ptr [[A]], i64 8
+; CHECK-NEXT:    [[DOTUNPACK2:%.*]] = load double, ptr [[DOTELT1]], align 8, !invariant.load [[META0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = insertvalue [[STRUCT_DOUBLE2]] [[TMP1]], double [[DOTUNPACK2]], 1
+; CHECK-NEXT:    ret [[STRUCT_DOUBLE2]] [[TMP2]]
+;
+  %1 = load %struct.double2, ptr %a, align 16, !invariant.load !1
+  ret %struct.double2 %1
+}
+
+define %struct.double1 @func3(ptr %a) {
+; CHECK-LABEL: define %struct.double1 @func3(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT:    [[DOTUNPACK:%.*]] = load double, ptr [[A]], align 16, !invariant.load [[META0]]
+; CHECK-NEXT:    [[TMP1:%.*]] = insertvalue [[STRUCT_DOUBLE1:%.*]] poison, double [[DOTUNPACK]], 0
+; CHECK-NEXT:    ret [[STRUCT_DOUBLE1]] [[TMP1]]
+;
+  %1 = load %struct.double1, ptr %a, align 16, !invariant.load !1
+  ret %struct.double1 %1
+}
+
+!1 = !{}