Merging r309353 and r309355:

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r309353 | davide | 2017-07-27 19:57:43 -0700 (Thu, 27 Jul 2017) | 3 lines

[JumpThreading] Add an option to dump LazyValueInfo after the run.

Differential Revision:  https://reviews.llvm.org/D35973
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r309355 | davide | 2017-07-27 20:10:43 -0700 (Thu, 27 Jul 2017) | 24 lines

[JumpThreading] Stop falsely preserving LazyValueInfo.

JumpThreading claims to preserve LVI, but it doesn't preserve
the analyses which LVI holds a reference to (e.g. the Dominator).
In the current pass manager infrastructure, after JT runs, the
PM frees these analyses (including DominatorTree) but preserves
LVI.

CorrelatedValuePropagation runs immediately after and queries
a corrupted domtree, causing weird miscompiles.

This commit disables the preservation of LVI for the time being.
Eventually, we should either move LVI to a proper dependency
tracking mechanism (i.e. an analyses shouldn't hold references
to other analyses and compute them on demand if needed), or
we should teach all the passes preserving LVI to preserve the
analyses LVI depends on.

The new pass manager has a mechanism to invalidate LVI in case
one of the analyses it depends on becomes invalid, so this problem
shouldn't exist (at least not in this immediate form), but handling
of analyses holding references is still a very delicate subject.

Fixes PR33917 (and rustc).
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_50@309439 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zmodem

lib/Transforms/Scalar/JumpThreading.cpp

@@ -64,6 +64,11 @@ ImplicationSearchThreshold(
            "condition to use to thread over a weaker condition"),
   cl::init(3), cl::Hidden);
 
+static cl::opt<bool> PrintLVIAfterJumpThreading(
+    "print-lvi-after-jump-threading",
+    cl::desc("Print the LazyValueInfo cache after JumpThreading"), cl::init(false),
+    cl::Hidden);
+
 namespace {
   /// This pass performs 'jump threading', which looks at blocks that have
   /// multiple predecessors and multiple successors.  If one or more of the
@@ -93,9 +98,10 @@ namespace {
     bool runOnFunction(Function &F) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      if (PrintLVIAfterJumpThreading)
+        AU.addRequired<DominatorTreeWrapperPass>();
       AU.addRequired<AAResultsWrapperPass>();
       AU.addRequired<LazyValueInfoWrapperPass>();
-      AU.addPreserved<LazyValueInfoWrapperPass>();
       AU.addPreserved<GlobalsAAWrapperPass>();
       AU.addRequired<TargetLibraryInfoWrapperPass>();
     }
@@ -137,8 +143,14 @@ bool JumpThreading::runOnFunction(Function &F) {
     BFI.reset(new BlockFrequencyInfo(F, *BPI, LI));
   }
 
-  return Impl.runImpl(F, TLI, LVI, AA, HasProfileData, std::move(BFI),
-                      std::move(BPI));
+  bool Changed = Impl.runImpl(F, TLI, LVI, AA, HasProfileData, std::move(BFI),
+                              std::move(BPI));
+  if (PrintLVIAfterJumpThreading) {
+    dbgs() << "LVI for function '" << F.getName() << "':\n";
+    LVI->printLVI(F, getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
+                  dbgs());
+  }
+  return Changed;
 }
 
 PreservedAnalyses JumpThreadingPass::run(Function &F,

test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll

@@ -1,4 +1,4 @@
-; RUN: opt < %s -jump-threading -print-lazy-value-info -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -jump-threading -print-lvi-after-jump-threading -disable-output 2>&1 | FileCheck %s
 
 ; Testing LVI cache after jump-threading
 
@@ -19,13 +19,10 @@ entry:
 ; CHECK-NEXT:     ; LatticeVal for: 'i32 %a' is: overdefined
 ; CHECK-NEXT:     ; LatticeVal for: 'i32 %length' is: overdefined
 ; CHECK-NEXT:     ; LatticeVal for: '  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%backedge' is: constantrange<0, 400>
-; CHECK-NEXT:     ; LatticeVal for: '  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%exit' is: constantrange<399, 400>
 ; CHECK-NEXT:  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
 ; CHECK-NEXT:     ; LatticeVal for: '  %iv.next = add nsw i32 %iv, 1' in BB: '%backedge' is: constantrange<1, 401>
-; CHECK-NEXT:     ; LatticeVal for: '  %iv.next = add nsw i32 %iv, 1' in BB: '%exit' is: constantrange<400, 401>
 ; CHECK-NEXT:  %iv.next = add nsw i32 %iv, 1
 ; CHECK-NEXT:     ; LatticeVal for: '  %cont = icmp slt i32 %iv.next, 400' in BB: '%backedge' is: overdefined
-; CHECK-NEXT:     ; LatticeVal for: '  %cont = icmp slt i32 %iv.next, 400' in BB: '%exit' is: constantrange<0, -1>
 ; CHECK-NEXT:  %cont = icmp slt i32 %iv.next, 400
 ; CHECK-NOT: loop
 loop:

test/Transforms/JumpThreading/pr33917.ll

@@ -0,0 +1,57 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -jump-threading -correlated-propagation %s -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare i8* @foo()
+
+declare i32 @rust_eh_personality() unnamed_addr
+
+; Function Attrs: nounwind
+declare void @llvm.assume(i1) #0
+
+define void @patatino() personality i32 ()* @rust_eh_personality {
+; CHECK-LABEL: @patatino(
+; CHECK-NEXT:  bb9:
+; CHECK-NEXT:    [[T9:%.*]] = invoke i8* @foo()
+; CHECK-NEXT:    to label [[GOOD:%.*]] unwind label [[BAD:%.*]]
+; CHECK:       bad:
+; CHECK-NEXT:    [[T10:%.*]] = landingpad { i8*, i32 }
+; CHECK-NEXT:    cleanup
+; CHECK-NEXT:    resume { i8*, i32 } [[T10]]
+; CHECK:       good:
+; CHECK-NEXT:    [[T11:%.*]] = icmp ne i8* [[T9]], null
+; CHECK-NEXT:    [[T12:%.*]] = zext i1 [[T11]] to i64
+; CHECK-NEXT:    [[COND:%.*]] = icmp eq i64 [[T12]], 1
+; CHECK-NEXT:    br i1 [[COND]], label [[IF_TRUE:%.*]], label [[DONE:%.*]]
+; CHECK:       if_true:
+; CHECK-NEXT:    call void @llvm.assume(i1 [[T11]])
+; CHECK-NEXT:    br label [[DONE]]
+; CHECK:       done:
+; CHECK-NEXT:    ret void
+;
+bb9:
+  %t9 = invoke i8* @foo()
+  to label %good unwind label %bad
+
+bad:
+  %t10 = landingpad { i8*, i32 }
+  cleanup
+  resume { i8*, i32 } %t10
+
+good:
+  %t11 = icmp ne i8* %t9, null
+  %t12 = zext i1 %t11 to i64
+  %cond = icmp eq i64 %t12, 1
+  br i1 %cond, label %if_true, label %done
+
+if_true:
+  call void @llvm.assume(i1 %t11)
+  br label %done
+
+done:
+  ret void
+}
+
+attributes #0 = { nounwind }