Recast operands as ints instead, per Florian2

Author: thurstond

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -2525,11 +2525,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
 
     Value *S = IRB.CreateOr({S1S2, V1S2, S1V2});
     if (ClPreciseDisjointOr && cast<PossiblyDisjointInst>(&I)->isDisjoint()) {
-      // "V1" and "V2" were NOT'ed above, but we still want to reuse them
-      // because they were IntCast'ed to the same type as the shadows.
-      //
-      // (V1 & V2) == ~(~V1 | ~V2) (de Morgan)
-      Value *V1V2 = IRB.CreateNot(IRB.CreateOr(V1, V2));
+      // "V1" and "V2" were NOT'ed above
+      V1 = IRB.CreateIntCast(I.getOperand(0), S1->getType(), false);
+      V2 = IRB.CreateIntCast(I.getOperand(1), S2->getType(), false);
+      Value *V1V2 = IRB.CreateAnd(V1, V2);
       S = IRB.CreateOr({S, V1V2});
     }
 

llvm/test/Instrumentation/MemorySanitizer/or.ll

@@ -45,11 +45,10 @@ define i8 @test_disjoint_or(i8 %a, i8 %b) sanitize_memory {
 ; CHECK-IMPRECISE:      [[C:%.*]] = or disjoint i8 [[A]], [[B]]
 ; CHECK-IMPRECISE-NEXT: store i8 [[TMP11]], ptr @__msan_retval_tls, align 8
 ;
-; CHECK-PRECISE:         [[TMP10:%.*]] = or i8 [[TMP3]], [[TMP4]]
-; CHECK-PRECISE-NEXT:    [[TMP11:%.*]] = xor i8 [[TMP10]], -1
-; CHECK-PRECISE-NEXT:    [[TMP12:%.*]] = or i8 [[TMP9]], [[TMP11]]
+; CHECK-PRECISE:         [[TMP10:%.*]] = and i8 [[A]], [[B]]
+; CHECK-PRECISE-NEXT:    [[TMP11:%.*]] = or i8 [[TMP9]], [[TMP10]]
 ; CHECK-PRECISE-NEXT:    [[C:%.*]] = or disjoint i8 [[A]], [[B]]
-; CHECK-PRECISE-NEXT:    store i8 [[TMP12]], ptr @__msan_retval_tls, align 8
+; CHECK-PRECISE-NEXT:    store i8 [[TMP11]], ptr @__msan_retval_tls, align 8
 ;
 ; CHECK-NEXT:    ret i8 [[C]]
 ;