[SimplifyCFG] Support not in chain of comparisons. (#156497)
Proof: https://alive2.llvm.org/ce/z/cpXuCb
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 86d4750..39edc4d 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -612,6 +612,9 @@
/// If CompValue is already set, the function is expected to fail if a match
/// is found but the value compared to is different.
bool matchInstruction(Instruction *I, bool isEQ) {
+ if (match(I, m_Not(m_Instruction(I))))
+ isEQ = !isEQ;
+
Value *Val;
if (match(I, m_NUWTrunc(m_Value(Val)))) {
// If we already have a value for the switch, it has to match!
diff --git a/llvm/test/Transforms/SimplifyCFG/switch_create.ll b/llvm/test/Transforms/SimplifyCFG/switch_create.ll
index 6d2a404..18c4ade 100644
--- a/llvm/test/Transforms/SimplifyCFG/switch_create.ll
+++ b/llvm/test/Transforms/SimplifyCFG/switch_create.ll
@@ -1265,3 +1265,51 @@
if.end:
ret void
}
+
+define void @and_chain_trunc_nuw_not_i1_condition(i8 %x) {
+; CHECK-LABEL: @and_chain_trunc_nuw_not_i1_condition(
+; CHECK-NEXT: [[X_OFF:%.*]] = add i8 [[X:%.*]], -1
+; CHECK-NEXT: [[SWITCH:%.*]] = icmp ult i8 [[X_OFF]], 4
+; CHECK-NEXT: br i1 [[SWITCH]], label [[COMMON_RET:%.*]], label [[IF_THEN:%.*]]
+; CHECK: common.ret:
+; CHECK-NEXT: ret void
+; CHECK: if.then:
+; CHECK-NEXT: tail call void @foo1()
+; CHECK-NEXT: br label [[COMMON_RET]]
+;
+ %add = add nsw i8 %x, -2
+ %icmp = icmp ugt i8 %add, 2
+ %trunc = trunc nuw i8 %x to i1
+ %not = xor i1 %trunc, true
+ %and = select i1 %icmp, i1 %not, i1 false
+ br i1 %and, label %if.then, label %if.end
+if.then:
+ tail call void @foo1()
+ ret void
+if.end:
+ ret void
+}
+
+define void @or_chain_trunc_nuw_not_i1_condition(i8 %x) {
+; CHECK-LABEL: @or_chain_trunc_nuw_not_i1_condition(
+; CHECK-NEXT: switch i8 [[X:%.*]], label [[COMMON_RET:%.*]] [
+; CHECK-NEXT: i8 2, label [[IF_THEN:%.*]]
+; CHECK-NEXT: i8 0, label [[IF_THEN]]
+; CHECK-NEXT: ]
+; CHECK: common.ret:
+; CHECK-NEXT: ret void
+; CHECK: if.then:
+; CHECK-NEXT: tail call void @foo1()
+; CHECK-NEXT: br label [[COMMON_RET]]
+;
+ %icmp = icmp eq i8 %x, 2
+ %trunc = trunc nuw i8 %x to i1
+ %not = xor i1 %trunc, true
+ %or = select i1 %icmp, i1 true, i1 %not
+ br i1 %or, label %if.then, label %if.end
+if.then:
+ tail call void @foo1()
+ ret void
+if.end:
+ ret void
+}
