Merge commit '2526d8c43499' from llvm.org/release/11.x into apple/stable/20200714

Author: git apple-llvm automerger

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -3837,10 +3837,7 @@ static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
     // TODO: This is an unusual limitation because better analysis results in
     //       worse simplification. InstCombine can do this fold more generally
     //       by dropping the flags. Remove this fold to save compile-time?
-    if (isa<OverflowingBinaryOperator>(B))
-      if (Q.IIQ.hasNoSignedWrap(B) || Q.IIQ.hasNoUnsignedWrap(B))
-        return nullptr;
-    if (isa<PossiblyExactOperator>(B) && Q.IIQ.isExact(B))
+    if (canCreatePoison(I))
       return nullptr;
 
     if (MaxRecurse) {

llvm/test/Transforms/InstSimplify/select.ll

@@ -919,3 +919,19 @@ define <2 x i32> @all_constant_true_undef_false_constexpr_vec() {
   %s = select i1 ptrtoint (<2 x i32> ()* @all_constant_true_undef_false_constexpr_vec to i1), <2 x i32> undef, <2 x i32><i32 -1, i32 ptrtoint (<2 x i32> ()* @all_constant_true_undef_false_constexpr_vec to i32)>
   ret <2 x i32> %s
 }
+
+define i32 @pr47322_more_poisonous_replacement(i32 %arg) {
+; CHECK-LABEL: @pr47322_more_poisonous_replacement(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[ARG:%.*]], 0
+; CHECK-NEXT:    [[TRAILING:%.*]] = call i32 @llvm.cttz.i32(i32 [[ARG]], i1 immarg true)
+; CHECK-NEXT:    [[SHIFTED:%.*]] = lshr i32 [[ARG]], [[TRAILING]]
+; CHECK-NEXT:    [[R1_SROA_0_1:%.*]] = select i1 [[CMP]], i32 0, i32 [[SHIFTED]]
+; CHECK-NEXT:    ret i32 [[R1_SROA_0_1]]
+;
+  %cmp = icmp eq i32 %arg, 0
+  %trailing = call i32 @llvm.cttz.i32(i32 %arg, i1 immarg true)
+  %shifted = lshr i32 %arg, %trailing
+  %r1.sroa.0.1 = select i1 %cmp, i32 0, i32 %shifted
+  ret i32 %r1.sroa.0.1
+}
+declare i32 @llvm.cttz.i32(i32, i1 immarg)