[MemoryLocation] Teach MemoryLocation about llvm.experimental.memset.pattern

Author: asb

llvm/lib/Analysis/MemoryLocation.cpp

@@ -183,6 +183,18 @@ MemoryLocation MemoryLocation::getForArgument(const CallBase *Call,
                               AATags);
       return MemoryLocation::getAfter(Arg, AATags);
 
+    case Intrinsic::experimental_memset_pattern:
+      assert((ArgIdx == 0 || ArgIdx == 1) &&
+             "Invalid argument index for memory intrinsic");
+      if (ConstantInt *LenCI = dyn_cast<ConstantInt>(II->getArgOperand(2)))
+        return MemoryLocation(
+            Arg,
+            LocationSize::precise(
+                LenCI->getZExtValue() *
+                DL.getTypeStoreSize(II->getArgOperand(1)->getType())),
+            AATags);
+      return MemoryLocation::getAfter(Arg, AATags);
+
     case Intrinsic::lifetime_start:
     case Intrinsic::lifetime_end:
     case Intrinsic::invariant_start:

llvm/test/Analysis/BasicAA/memset-pattern.ll

@@ -4,7 +4,7 @@ define void @test_memset_pattern4_const_size(ptr noalias %a, i32 %pattern) {
 ; CHECK-LABEL: Function: test_memset_pattern4_const_size
 ; CHECK:      Just Mod:  Ptr: i8* %a	<->  call void @llvm.experimental.memset.pattern.p0.i32.i64(ptr %a, i32 %pattern, i64 17, i1 false)
 ; CHECK-NEXT: Just Mod:  Ptr: i8* %a.gep.1	<->  call void @llvm.experimental.memset.pattern.p0.i32.i64(ptr %a, i32 %pattern, i64 17, i1 false)
-; CHECK-NEXT: Just Mod:  Ptr: i8* %a.gep.129	<->  call void @llvm.experimental.memset.pattern.p0.i32.i64(ptr %a, i32 %pattern, i64 17, i1 false)
+; CHECK-NEXT: NoModRef:  Ptr: i8* %a.gep.129	<->  call void @llvm.experimental.memset.pattern.p0.i32.i64(ptr %a, i32 %pattern, i64 17, i1 false)
 
 entry:
   load i8, ptr %a