[JumpThreading][LVI] Invalidate LVI information after blocks are merged

Summary:
After a single predecessor is merged into a basic block, we need to invalidate
the LVI information for the new merged block, when LVI is not provably true for
all of instructions in the new block.
The test cases added show the correct LVI information using the LVI printer
pass.

Reviewers: reames, dberlin, davide, sanjoy

Reviewed by: dberlin, davide

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34108

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305699 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 87 insertions, 0 deletions

diff --git a/test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll b/test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll
index 3a0ab0f03b9..e797b377556 100644
--- a/test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll
+++ b/test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll
@@ -100,3 +100,90 @@ backedge:
 exit:
   ret i8 0
 }
+
+; Merging cont block into do block. Make sure that we do not incorrectly have the cont
+; LVI info as LVI info for the beginning of do block. LVI info for %i is Range[0,1)
+; at beginning of cont Block, which is incorrect at the beginning of do block.
+define i32 @test3(i32 %i, i1 %f, i32 %n) {
+; CHECK-LABEL: LVI for function 'test3':
+; CHECK-LABEL: entry
+; CHECK:  ; LatticeVal for: 'i32 %i' is: overdefined
+; CHECK: %c = icmp ne i32 %i, -2134 
+; CHECK: br i1 %c, label %cont, label %exit
+entry:
+  %c = icmp ne i32 %i, -2134
+  br i1 %c, label %do, label %exit
+
+exit:
+  %c1 = icmp ne i32 %i, -42
+  br i1 %c1, label %exit2, label %exit
+
+; CHECK-LABEL: cont:
+; Here cont is merged to do and i is any value except -2134.
+; i is not the single value: zero.
+; CHECK-NOT:  ; LatticeVal for: 'i32 %i' is: constantrange<0, 1>
+; CHECK:      ; LatticeVal for: 'i32 %i' is: constantrange<-2133, -2134>
+; CHECK:      ; LatticeVal for: '  %cond.0 = icmp sgt i32 %i, 0' in BB: '%cont' is: overdefined
+; CHECK:   %cond.0 = icmp sgt i32 %i, 0
+; CHECK:   %consume = call i32 @consume
+; CHECK:   %cond = icmp eq i32 %i, 0
+; CHECK:   call void (i1, ...) @llvm.experimental.guard(i1 %cond)
+; CHECK:   %cond.3 = icmp sgt i32 %i, %n
+; CHECK:   br i1 %cond.3, label %exit2, label %exit
+cont:
+  %cond.3 = icmp sgt i32 %i, %n
+  br i1 %cond.3, label %exit2, label %exit
+
+do:
+  %cond.0 = icmp sgt i32 %i, 0
+  %consume = call i32 @consume(i1 %cond.0)
+  %cond = icmp eq i32 %i, 0
+  call void (i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
+  %cond.2 = icmp sgt i32 %i, 0
+  br i1 %cond.2, label %exit, label %cont
+  
+exit2:
+; CHECK-LABEL: exit2:
+; LatticeVal for: 'i32 %i' is: constantrange<-2134, 1>
+  ret i32 30
+}
+
+; FIXME: We should be able to merge cont into do.
+; When we do so, LVI for cont cannot be the one for the merged do block.
+define i32 @test4(i32 %i, i1 %f, i32 %n) {
+; CHECK-LABEL: LVI for function 'test4':
+entry:
+  %c = icmp ne i32 %i, -2134
+  br i1 %c, label %do, label %exit
+
+exit:                                             ; preds = %do, %cont, %exit, %entry
+  %c1 = icmp ne i32 %i, -42
+  br i1 %c1, label %exit2, label %exit
+
+cont:                                             ; preds = %do
+; CHECK-LABEL: cont:
+; CHECK:  ; LatticeVal for: 'i1 %f' is: constantrange<-1, 0>
+; CHECK: call void @dummy(i1 %f)
+  call void @dummy(i1 %f)
+  br label %exit2
+
+do:                                               ; preds = %entry
+; CHECK-LABEL: do:
+; CHECK:  ; LatticeVal for: 'i1 %f' is: overdefined
+; CHECK: call void @dummy(i1 %f)
+; CHECK: br i1 %cond, label %exit, label %cont
+  call void @dummy(i1 %f)
+  %consume = call i32 @exit()
+  call void @llvm.assume(i1 %f)
+  %cond = icmp eq i1 %f, false
+  br i1 %cond, label %exit, label %cont
+
+exit2:                                            ; preds = %cont, %exit
+  ret i32 30
+}
+
+declare i32 @exit()
+declare i32 @consume(i1)
+declare void @llvm.assume(i1) nounwind
+declare void @dummy(i1) nounwind
+declare void @llvm.experimental.guard(i1, ...)