[InstCombine] Add more tests for unreachable code (NFC)

Author: nikic

llvm/test/Transforms/InstCombine/unreachable-code.ll

@@ -228,6 +228,32 @@ join:
   ret i32 %phi
 }
 
+define void @non_term_unreachable_following_blocks() {
+; CHECK-LABEL: define void @non_term_unreachable_following_blocks() {
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    br label [[SPLIT:%.*]]
+; CHECK:       split:
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    br label [[LOOP]]
+;
+  call void @dummy()
+  store i1 true, ptr poison
+  call void @dummy()
+  br label %split
+
+split:
+  call void @dummy()
+  br label %loop
+
+loop:
+  call void @dummy()
+  br label %loop
+}
+
 define void @br_not_into_loop(i1 %x) {
 ; CHECK-LABEL: define void @br_not_into_loop
 ; CHECK-SAME: (i1 [[X:%.*]]) {
@@ -271,6 +297,128 @@ exit:
   call void @dummy()
   ret void
 }
-;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
-; DEFAULT_ITER: {{.*}}
-; MAX1: {{.*}}
+
+define void @two_br_not_into_loop(i1 %x) {
+; DEFAULT_ITER-LABEL: define void @two_br_not_into_loop
+; DEFAULT_ITER-SAME: (i1 [[X:%.*]]) {
+; DEFAULT_ITER-NEXT:    br i1 true, label [[BB2:%.*]], label [[LOOP:%.*]]
+; DEFAULT_ITER:       bb2:
+; DEFAULT_ITER-NEXT:    br i1 true, label [[EXIT:%.*]], label [[LOOP]]
+; DEFAULT_ITER:       loop:
+; DEFAULT_ITER-NEXT:    br label [[LOOP]]
+; DEFAULT_ITER:       exit:
+; DEFAULT_ITER-NEXT:    call void @dummy()
+; DEFAULT_ITER-NEXT:    ret void
+;
+; MAX1-LABEL: define void @two_br_not_into_loop
+; MAX1-SAME: (i1 [[X:%.*]]) {
+; MAX1-NEXT:    br i1 true, label [[BB2:%.*]], label [[LOOP:%.*]]
+; MAX1:       bb2:
+; MAX1-NEXT:    br i1 true, label [[EXIT:%.*]], label [[LOOP]]
+; MAX1:       loop:
+; MAX1-NEXT:    call void @dummy()
+; MAX1-NEXT:    br label [[LOOP]]
+; MAX1:       exit:
+; MAX1-NEXT:    call void @dummy()
+; MAX1-NEXT:    ret void
+;
+  %c = or i1 %x, true
+  br i1 %c, label %bb2, label %loop
+
+bb2:
+  %c2 = or i1 %x, true
+  br i1 %c2, label %exit, label %loop
+
+loop:
+  call void @dummy()
+  br label %loop
+
+exit:
+  call void @dummy()
+  ret void
+}
+
+define void @one_br_into_loop_one_not(i1 %x, i1 %c2) {
+; CHECK-LABEL: define void @one_br_into_loop_one_not
+; CHECK-SAME: (i1 [[X:%.*]], i1 [[C2:%.*]]) {
+; CHECK-NEXT:    br i1 true, label [[BB2:%.*]], label [[LOOP:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    br i1 [[C2]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    br label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    ret void
+;
+  %c = or i1 %x, true
+  br i1 %c, label %bb2, label %loop
+
+bb2:
+  br i1 %c2, label %exit, label %loop
+
+loop:
+  call void @dummy()
+  br label %loop
+
+exit:
+  call void @dummy()
+  ret void
+}
+
+define void @two_br_not_into_loop_with_split(i1 %x) {
+; DEFAULT_ITER-LABEL: define void @two_br_not_into_loop_with_split
+; DEFAULT_ITER-SAME: (i1 [[X:%.*]]) {
+; DEFAULT_ITER-NEXT:    br i1 true, label [[BB2:%.*]], label [[SPLIT1:%.*]]
+; DEFAULT_ITER:       bb2:
+; DEFAULT_ITER-NEXT:    br i1 true, label [[EXIT:%.*]], label [[SPLIT2:%.*]]
+; DEFAULT_ITER:       split1:
+; DEFAULT_ITER-NEXT:    br label [[LOOP:%.*]]
+; DEFAULT_ITER:       split2:
+; DEFAULT_ITER-NEXT:    br label [[LOOP]]
+; DEFAULT_ITER:       loop:
+; DEFAULT_ITER-NEXT:    br label [[LOOP]]
+; DEFAULT_ITER:       exit:
+; DEFAULT_ITER-NEXT:    call void @dummy()
+; DEFAULT_ITER-NEXT:    ret void
+;
+; MAX1-LABEL: define void @two_br_not_into_loop_with_split
+; MAX1-SAME: (i1 [[X:%.*]]) {
+; MAX1-NEXT:    br i1 true, label [[BB2:%.*]], label [[SPLIT1:%.*]]
+; MAX1:       bb2:
+; MAX1-NEXT:    br i1 true, label [[EXIT:%.*]], label [[SPLIT2:%.*]]
+; MAX1:       split1:
+; MAX1-NEXT:    br label [[LOOP:%.*]]
+; MAX1:       split2:
+; MAX1-NEXT:    br label [[LOOP]]
+; MAX1:       loop:
+; MAX1-NEXT:    call void @dummy()
+; MAX1-NEXT:    br label [[LOOP]]
+; MAX1:       exit:
+; MAX1-NEXT:    call void @dummy()
+; MAX1-NEXT:    ret void
+;
+  %c = or i1 %x, true
+  br i1 %c, label %bb2, label %split1
+
+bb2:
+  %c2 = or i1 %x, true
+  br i1 %c2, label %exit, label %split2
+
+split1:
+  call void @dummy()
+  br label %loop
+
+split2:
+  call void @dummy()
+  br label %loop
+
+loop:
+  call void @dummy()
+  br label %loop
+
+exit:
+  call void @dummy()
+  ret void
+}
+