From 89b19e8959510cd52094394fb1e46e37bb5a2c09 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Fri, 13 Mar 2020 14:36:26 -0400
Subject: [PATCH] [SimplifyCFG] add test for chain of empty block conditional
 branches; NFC

---
 llvm/test/Transforms/SimplifyCFG/extract-cost.ll | 51 ++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 3 deletions(-)

diff --git a/llvm/test/Transforms/SimplifyCFG/extract-cost.ll b/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
index 9c86725..0a544f5 100644
--- a/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
+++ b/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
@@ -1,8 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -simplifycfg -S  < %s | FileCheck %s
 
 declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32) #1
 
 define i32 @f(i32 %a, i32 %b) #0 {
+; CHECK-LABEL: @f(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UADD:%.*]] = tail call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 [[A:%.*]], i32 [[B:%.*]])
+; CHECK-NEXT:    [[CMP:%.*]] = extractvalue { i32, i1 } [[UADD]], 1
+; CHECK-NEXT:    [[TMP0:%.*]] = extractvalue { i32, i1 } [[UADD]], 0
+; CHECK-NEXT:    [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 0, i32 [[TMP0]]
+; CHECK-NEXT:    ret i32 [[SPEC_SELECT]]
+;
 entry:
   %uadd = tail call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
   %cmp = extractvalue { i32, i1 } %uadd, 1
@@ -15,8 +24,44 @@ if.end:                                           ; preds = %entry
 return:                                           ; preds = %entry, %if.end
   %retval.0 = phi i32 [ %0, %if.end ], [ 0, %entry ]
   ret i32 %retval.0
+}
 
-; CHECK-LABEL: @f(
-; CHECK-NOT: phi
-; CHECK: select
+define i1 @PR32078(<4 x i32> %a, <4 x i32> %b) {
+; CHECK-LABEL: @PR32078(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <4 x i32> [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[CMP0:%.*]] = extractelement <4 x i1> [[CMP]], i32 0
+; CHECK-NEXT:    [[CMP1:%.*]] = extractelement <4 x i1> [[CMP]], i32 1
+; CHECK-NEXT:    [[CMP2:%.*]] = extractelement <4 x i1> [[CMP]], i32 2
+; CHECK-NEXT:    [[CMP3:%.*]] = extractelement <4 x i1> [[CMP]], i32 3
+; CHECK-NEXT:    [[CMP0_NOT:%.*]] = xor i1 [[CMP0]], true
+; CHECK-NEXT:    [[CMP1_NOT:%.*]] = xor i1 [[CMP1]], true
+; CHECK-NEXT:    [[BRMERGE:%.*]] = or i1 [[CMP0_NOT]], [[CMP1_NOT]]
+; CHECK-NEXT:    br i1 [[BRMERGE]], label [[EXIT:%.*]], label [[CMP1_TRUE:%.*]]
+; CHECK:       cmp1_true:
+; CHECK-NEXT:    [[SPEC_SELECT:%.*]] = select i1 [[CMP2]], i1 [[CMP3]], i1 false
+; CHECK-NEXT:    ret i1 [[SPEC_SELECT]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp eq <4 x i32> %a, %b
+  %cmp0 = extractelement <4 x i1> %cmp, i32 0
+  %cmp1 = extractelement <4 x i1> %cmp, i32 1
+  %cmp2 = extractelement <4 x i1> %cmp, i32 2
+  %cmp3 = extractelement <4 x i1> %cmp, i32 3
+  br i1 %cmp0, label %cmp0_true, label %exit
+
+cmp0_true:
+  br i1 %cmp1, label %cmp1_true, label %exit
+
+cmp1_true:
+  br i1 %cmp2, label %cmp2_true, label %exit
+
+cmp2_true:
+  br label %exit
+
+exit:
+  %r = phi i1 [ false, %cmp0_true ], [ false, %cmp1_true ], [ false, %entry ], [ %cmp3, %cmp2_true ]
+  ret i1 %r
 }
-- 
2.7.4