Merging r321789:

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r321789 | hiraditya | 2018-01-03 23:47:24 -0800 (Wed, 03 Jan 2018) | 8 lines

[GVNHoist] Fix: PR35222 gvn-hoist incorrectly erases load in case of a loop

Reviewers:
    dberlin
    sebpop
    eli.friedman

Differential Revision: https://reviews.llvm.org/D41453
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@322558 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 46 insertions, 1 deletions

diff --git a/lib/Transforms/Scalar/GVNHoist.cpp b/lib/Transforms/Scalar/GVNHoist.cpp
index c0cd1ea74a7..026fab5dbd3 100644
--- a/lib/Transforms/Scalar/GVNHoist.cpp
+++ b/lib/Transforms/Scalar/GVNHoist.cpp
@@ -648,7 +648,7 @@ private:
           // track in a CHI. In the PDom walk, there can be values in the
           // stack which are not control dependent e.g., nested loop.
           if (si != RenameStack.end() && si->second.size() &&
-              DT->dominates(Pred, si->second.back()->getParent())) {
+              DT->properlyDominates(Pred, si->second.back()->getParent())) {
             C.Dest = BB;                     // Assign the edge
             C.I = si->second.pop_back_val(); // Assign the argument
             DEBUG(dbgs() << "\nCHI Inserted in BB: " << C.Dest->getName()
diff --git a/test/Transforms/GVNHoist/pr35222-hoist-load.ll b/test/Transforms/GVNHoist/pr35222-hoist-load.ll
index 7e9c6200616..b9b1a870a59 100644
--- a/test/Transforms/GVNHoist/pr35222-hoist-load.ll
+++ b/test/Transforms/GVNHoist/pr35222-hoist-load.ll
@@ -1,4 +1,5 @@
 ; RUN: opt -S -gvn-hoist < %s | FileCheck %s
+; CHECK-LABEL: build_tree
 ; CHECK: load
 ; CHECK: load
 ; Check that the load is not hoisted because the call can potentially
@@ -23,3 +24,47 @@ do.end:                                           ; preds = %do.body
 }
 
 declare i1 @pqdownheap(i32)
+
+@i = external hidden unnamed_addr global i32, align 4
+@j = external hidden unnamed_addr global [573 x i32], align 4
+@v = external global i1
+
+; CHECK-LABEL: test
+; CHECK-LABEL: do.end
+; CHECK: load
+; Check that the load is not hoisted because the call can potentially
+; modify the global
+
+define i32 @test() {
+entry:
+  br label %for.cond
+
+for.cond:
+  %a3 = load volatile i1, i1* @v
+  br i1 %a3, label %for.body, label %while.end
+
+for.body:
+  br label %if.then
+
+if.then:
+  %tmp4 = load i32, i32* @i, align 4
+  br label %for.cond
+
+while.end:
+  br label %do.body
+
+do.body:
+  %tmp9 = load i32, i32* getelementptr inbounds ([573 x i32], [573 x i32]* @j,
+i32 0, i32 1), align 4
+  %tmp10 = load i32, i32* @i, align 4
+  call void @fn()
+  %a1 = load volatile i1, i1* @v
+  br i1 %a1, label %do.body, label %do.end
+
+do.end:
+  %tmp20 = load i32, i32* getelementptr inbounds ([573 x i32], [573 x i32]* @j,
+i32 0, i32 1), align 4
+  ret i32 %tmp20
+}
+
+declare void @fn()