[InstCombine] Look through invariant group intrinsics when removing malloc

[aeubanks]

Summary

Fixes some regressions with -fstrict-vtable-pointers in llvm-test-suite.

[lebedev.ri]

LG

llvm/test/Transforms/InstCombine/malloc-free-delete.ll

441

Please precommit

[aeubanks]

precommit test

[Prazek]

Sorry for late reply. Although I don't have experience in this pass, it looks good!

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

for (User *U : PI->users()) {
           case Intrinsic::assume:
           case Intrinsic::invariant_start:
           case Intrinsic::invariant_end:
           case Intrinsic::lifetime_start:
           case Intrinsic::lifetime_end:
           case Intrinsic::objectsize:
             Users.emplace_back(I);
             continue;
+          case Intrinsic::launder_invariant_group:
+          case Intrinsic::strip_invariant_group:
+            Users.emplace_back(I);
+            Worklist.push_back(I);
+            continue;
           }
         }
 
         if (isFreeCall(I, TLI)) {
           Users.emplace_back(I);
           continue;
         }
         return false;

llvm/test/Transforms/InstCombine/malloc-free-delete.ll

 ;
   call void @free(i8* %foo)
   ret void
 }
 
 declare i8* @llvm.launder.invariant.group(i8*)
 declare i8* @llvm.strip.invariant.group(i8*)
 
 define void @test17() {
 ; CHECK-LABEL: @test17(
-; CHECK-NEXT:    [[NW1:%.*]] = call dereferenceable(32) i8* @_Znwm(i64 32) #[[ATTR10]]
-; CHECK-NEXT:    [[NW2:%.*]] = call i8* @llvm.launder.invariant.group.p0i8(i8* nonnull [[NW1]])
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8* @llvm.strip.invariant.group.p0i8(i8* nonnull [[NW1]])
-; CHECK-NEXT:    store i8 1, i8* [[TMP1]], align 1
-; CHECK-NEXT:    call void @_ZdlPv(i8* [[NW2]]) #[[ATTR10]]
 ; CHECK-NEXT:    ret void
 ;
   %nw1 = call i8* @_Znwm(i64 32) builtin
   %nw2 = call i8* @llvm.launder.invariant.group(i8* %nw1)
   %nw3 = call i8* @llvm.strip.invariant.group(i8* %nw2)
   store i8 1, i8* %nw3
   call void @_ZdlPv(i8* %nw2) builtin
   ret void
 }