From 834b45129bb3e9cbaef97f1118819c523a6edc68 Mon Sep 17 00:00:00 2001
From: Davide Italiano <davide@freebsd.org>
Date: Mon, 30 Oct 2017 20:20:16 +0000
Subject: [PATCH] [NewGVN] Stop assuming PHI args ordering when looking at
 phi-of-ops.

It's not guaranteed. There's a bug open to sort them in predecessor
order, but it won't happen anytime soon. In the meanwhile, passes
will have to do an O(#preds) scan. Such is life.

llvm-svn: 316953
---
 llvm/lib/Transforms/Scalar/NewGVN.cpp  |  2 +-
 llvm/test/Transforms/NewGVN/pr35125.ll | 70 ++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/Transforms/NewGVN/pr35125.ll

diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index a7f2793..9ebf2d7 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -2766,7 +2766,7 @@ NewGVN::makePossiblePHIOfOps(Instruction *I,
               Deps.insert(Op);
           } else if (auto *ValuePHI = RealToTemp.lookup(Op)) {
             if (getBlockForValue(ValuePHI) == PHIBlock)
-              Op = ValuePHI->getIncomingValue(PredNum);
+              Op = ValuePHI->getIncomingValueForBlock(PredBB);
           }
           // If we phi-translated the op, it must be safe.
           SafeForPHIOfOps =
diff --git a/llvm/test/Transforms/NewGVN/pr35125.ll b/llvm/test/Transforms/NewGVN/pr35125.ll
new file mode 100644
index 0000000..ed9d513
--- /dev/null
+++ b/llvm/test/Transforms/NewGVN/pr35125.ll
@@ -0,0 +1,70 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -newgvn -S %s | FileCheck %s
+
+@a = common global i32 0, align 4
+@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+define i32 @main() #0 {
+; CHECK-LABEL: @main(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = load i32, i32* @a, align 4
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[TMP0]], -1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], -1
+; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
+; CHECK:       if.then:
+; CHECK-NEXT:    br label [[IF_END]]
+; CHECK:       if.end:
+; CHECK-NEXT:    [[PHIOFOPS:%.*]] = phi i32 [ [[TMP0]], [[ENTRY:%.*]] ], [ [[NEG]], [[IF_THEN]] ]
+; CHECK-NEXT:    [[STOREMERGE:%.*]] = phi i32 [ [[TMP0]], [[IF_THEN]] ], [ [[NEG]], [[ENTRY]] ]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[STOREMERGE]], [[PHIOFOPS]]
+; CHECK-NEXT:    br i1 [[CMP2]], label [[IF_THEN3:%.*]], label [[IF_END6:%.*]]
+; CHECK:       if.then3:
+; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[STOREMERGE]], -1
+; CHECK-NEXT:    br i1 [[TOBOOL]], label [[LOR_RHS:%.*]], label [[LOR_END:%.*]]
+; CHECK:       lor.rhs:
+; CHECK-NEXT:    [[TOBOOL5:%.*]] = icmp ne i32 [[TMP0]], 0
+; CHECK-NEXT:    [[PHITMP:%.*]] = zext i1 [[TOBOOL5]] to i32
+; CHECK-NEXT:    br label [[LOR_END]]
+; CHECK:       lor.end:
+; CHECK-NEXT:    [[TMP1:%.*]] = phi i32 [ 1, [[IF_THEN3]] ], [ [[PHITMP]], [[LOR_RHS]] ]
+; CHECK-NEXT:    store i32 [[TMP1]], i32* @a, align 4
+; CHECK-NEXT:    br label [[IF_END6]]
+; CHECK:       if.end6:
+; CHECK-NEXT:    [[TMP2:%.*]] = load i32, i32* @a, align 4
+; CHECK-NEXT:    [[CALL:%.*]] = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 [[TMP2]])
+; CHECK-NEXT:    ret i32 0
+;
+entry:
+  %0 = load i32, i32* @a, align 4
+  %neg = xor i32 %0, -1
+  %cmp = icmp sgt i32 %0, -1
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+  br label %if.end
+
+if.end:
+  %storemerge = phi i32 [ %0, %if.then ], [ %neg, %entry ]
+  %neg1 = xor i32 %storemerge, -1
+  %cmp2 = icmp ult i32 %storemerge, %neg1
+  br i1 %cmp2, label %if.then3, label %if.end6
+
+if.then3:
+  %tobool = icmp eq i32 %storemerge, -1
+  br i1 %tobool, label %lor.rhs, label %lor.end
+
+lor.rhs:
+  %tobool5 = icmp ne i32 %0, 0
+  %phitmp = zext i1 %tobool5 to i32
+  br label %lor.end
+
+lor.end:
+  %1 = phi i32 [ 1, %if.then3 ], [ %phitmp, %lor.rhs ]
+  store i32 %1, i32* @a, align 4
+  br label %if.end6
+
+if.end6:
+  %2 = load i32, i32* @a, align 4
+  %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 %2) #3
+  ret i32 0
+}
+declare i32 @printf(i8*, ...) #2
-- 
2.7.4