When marking a block as being unanalyzable, use "Clobber" on the terminator instead...

In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated).

The included testcase tests both this commit and r132434.

Part two of rdar://9429882.  (r132434 was mislabeled.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132442 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index e854f7c068e755040c0bb736a8e23aac6a072cc0..a412425770f7de4ba82fa42209e5373f506d1c72 100644 (file)
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -1155,8 +1155,8 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
       
       assert(I->getResult().isNonLocal() &&
              "Should only be here with transparent block");
-      I->setResult(MemDepResult::getClobber(BB->begin()));
-      ReverseNonLocalPtrDeps[BB->begin()].insert(CacheKey);
+      I->setResult(MemDepResult::getClobber(BB->getTerminator()));
+      ReverseNonLocalPtrDeps[BB->getTerminator()].insert(CacheKey);
       Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(),
                                          Pointer.getAddr()));
       break;

diff --git a/test/Transforms/GVN/2011-06-01-NonLocalMemdepMiscompile.ll b/test/Transforms/GVN/2011-06-01-NonLocalMemdepMiscompile.ll
new file mode 100644 (file)
index 0000000..f24e956
--- /dev/null
+++ b/test/Transforms/GVN/2011-06-01-NonLocalMemdepMiscompile.ll
@@ -0,0 +1,61 @@
+; RUN: opt < %s -basicaa -gvn -S | FileCheck %s
+; This test is checking that (a) this doesn't crash, and (b) we don't
+; conclude the value of %tmp17 is available in bb1.bb15_crit_edge.
+; rdar://9429882
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-macosx10.7.0"
+
+define i1 @rb_intern() nounwind ssp {
+; CHECK: @rb_intern
+
+bb:
+  %tmp = alloca i8*, align 8
+  store i8* null, i8** %tmp, align 8
+  store i8 undef, i8* null, align 536870912
+  br label %bb1
+
+bb1:
+  br i1 undef, label %bb3, label %bb15
+
+; CHECK: bb1:
+; CHECK: %tmp16 = phi i8* [ getelementptr (i8* null, i64 undef), %bb10 ], [ null, %bb ]
+
+; CHECK: bb1.bb15_crit_edge:
+; CHECK: %tmp17.pre = load i8* %tmp16, align 1
+
+bb3:
+  call void @isalnum()
+  br i1 undef, label %bb10, label %bb5
+
+bb5:
+  br i1 undef, label %bb10, label %bb6
+
+bb6:
+  %tmp7 = load i8** %tmp, align 8
+  %tmp8 = load i8* %tmp7, align 1
+  %tmp9 = zext i8 %tmp8 to i64
+  br i1 undef, label %bb15, label %bb10
+
+bb10:
+  %tmp11 = load i8** %tmp, align 8
+  %tmp12 = load i8* %tmp11, align 1
+  %tmp13 = zext i8 %tmp12 to i64
+  %tmp14 = getelementptr inbounds i8* null, i64 undef
+  store i8* %tmp14, i8** %tmp, align 8
+  br label %bb1
+
+bb15:
+  %tmp16 = load i8** %tmp, align 8
+  %tmp17 = load i8* %tmp16, align 1
+  %tmp18 = icmp eq i8 %tmp17, 0
+  br label %bb19
+
+; CHECK: bb15:
+; CHECK: %tmp17 = phi i8 [ %tmp17.pre, %bb1.bb15_crit_edge ], [ %tmp8, %bb6 ]
+
+bb19:                                             ; preds = %bb15
+  ret i1 %tmp18
+}
+
+declare void @isalnum() nounwind inlinehint ssp