Make jump threading honor x|undef -> true and x&undef -> false,

instead of considering x|undef -> x, which may not be true.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95850 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 3eff3d8d23d4d775ff1ce068ffac104de326718c..02346a135f498b222a1dc55e61a0b3b239c83874 100644 (file)
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -336,13 +336,18 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
       else
         InterestingVal = ConstantInt::getFalse(I->getContext());
       
-      // Scan for the sentinel.
+      // Scan for the sentinel.  If we find an undef, force it to the
+      // interesting value: x|undef -> true and x&undef -> false.
       for (unsigned i = 0, e = LHSVals.size(); i != e; ++i)
-        if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0)
+        if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0) {
           Result.push_back(LHSVals[i]);
+          Result.back().first = InterestingVal;
+        }
       for (unsigned i = 0, e = RHSVals.size(); i != e; ++i)
-        if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0)
+        if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) {
           Result.push_back(RHSVals[i]);
+          Result.back().first = InterestingVal;
+        }
       return !Result.empty();
     }
     

diff --git a/test/Transforms/JumpThreading/or-undef.ll b/test/Transforms/JumpThreading/or-undef.ll
new file mode 100644 (file)
index 0000000..6e35992
--- /dev/null
+++ b/test/Transforms/JumpThreading/or-undef.ll
@@ -0,0 +1,69 @@
+; RUN: opt -jump-threading -S %s | FileCheck %s
+; rdar://7620633
+
+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-darwin11.0"
+
+define void @test1(i8* %args, i32 %from_tty) nounwind optsize ssp {
+entry:
+  %tmp = call i8* @f3(void (i8*)* null, i8* null) nounwind ; <i8*> [#uses=1]
+  %tmp1 = icmp eq i8* %args, null                 ; <i1> [#uses=1]
+  br i1 %tmp1, label %bb2, label %bb
+
+; CHECK: entry:
+; CHECK-NEXT: %tmp = call i8* @f3
+; CHECK-NEXT: %tmp1 = icmp eq i8* %args, null
+; CHECK-NEXT: br i1 %tmp1, label %bb7, label %bb
+
+bb:                                               ; preds = %entry
+  %tmp2 = call noalias i8** @buildargv(i8* %args) nounwind ; <i8**> [#uses=4]
+  %tmp3 = icmp eq i8** %tmp2, null                ; <i1> [#uses=1]
+  br i1 %tmp3, label %bb2, label %bb1
+
+bb1:                                              ; preds = %bb
+  call void @f2(i8** %tmp2) nounwind
+  br label %bb2
+
+bb2:                                              ; preds = %bb1, %bb, %entry
+  %argv.0 = phi i8** [ %tmp2, %bb1 ], [ %tmp2, %bb ], [ undef, %entry ] ; <i8**> [#uses=4]
+  %tmp5 = icmp eq i8* %args, null                 ; <i1> [#uses=1]
+  %tmp6 = icmp eq i8** %argv.0, null              ; <i1> [#uses=1]
+  %tmp7 = or i1 %tmp5, %tmp6                      ; <i1> [#uses=1]
+  br i1 %tmp7, label %bb7, label %bb5
+
+bb5:                                              ; preds = %bb2
+  %tmp8 = load i8** %argv.0, align 8              ; <i8*> [#uses=1]
+  %tmp9 = icmp eq i8* %tmp8, null                 ; <i1> [#uses=1]
+  br i1 %tmp9, label %bb7, label %bb6
+
+bb6:                                              ; preds = %bb5
+  %tmp10 = load i8** %argv.0, align 8             ; <i8*> [#uses=1]
+  %tmp11 = load i8* %tmp10, align 1               ; <i8> [#uses=1]
+  %tmp12 = icmp eq i8 %tmp11, 0                   ; <i1> [#uses=1]
+  br i1 %tmp12, label %bb7, label %bb8
+
+bb7:                                              ; preds = %bb6, %bb5, %bb2
+  call void @f1() nounwind optsize ssp
+  br label %bb9
+
+bb8:                                              ; preds = %bb6
+  %tmp13 = load i8** %argv.0, align 8             ; <i8*> [#uses=1]
+  %tmp14 = call i64 @f5(i8* %tmp13) nounwind      ; <i64> [#uses=0]
+  br label %bb9
+
+bb9:                                              ; preds = %bb8, %bb7
+  call void @f4(i8* %tmp) nounwind
+  ret void
+}
+
+declare noalias i8** @buildargv(i8*)
+
+declare void @f2(i8**)
+
+declare void @f4(i8*)
+
+declare i8* @f3(void (i8*)*, i8*)
+
+declare void @f1()
+
+declare i64 @f5(i8*)