Reapply r166405, teaching tailcallelim to be smarter about nocapture, with a

very small but very important bugfix:
  bool shouldExplore(Use *U) {
    Value *V = U->get();
    if (isa<CallInst>(V) || isa<InvokeInst>(V))
    [...]
should have read:
  bool shouldExplore(Use *U) {
    Value *V = U->getUser();
    if (isa<CallInst>(V) || isa<InvokeInst>(V))
Fixes PR14143!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166407 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 4 deletions

diff --git a/test/Transforms/TailCallElim/nocapture.ll b/test/Transforms/TailCallElim/nocapture.ll
index 87cb9dd427..5a1a9a6e7c 100644
--- a/test/Transforms/TailCallElim/nocapture.ll
+++ b/test/Transforms/TailCallElim/nocapture.ll
@@ -1,9 +1,9 @@
 ; RUN: opt %s -tailcallelim -S | FileCheck %s
-; XFAIL: *
 
 declare void @use(i8* nocapture, i8* nocapture)
+declare void @boring()
 
-define i8* @foo(i8* nocapture %A, i1 %cond) {
+define i8* @test1(i8* nocapture %A, i1 %cond) {
 ; CHECK: tailrecurse:
 ; CHECK: %A.tr = phi i8* [ %A, %0 ], [ %B, %cond_true ]
 ; CHECK: %cond.tr = phi i1 [ %cond, %0 ], [ false, %cond_true ]
@@ -14,12 +14,27 @@ define i8* @foo(i8* nocapture %A, i1 %cond) {
 cond_true:
 ; CHECK: cond_true:
 ; CHECK: br label %tailrecurse
-  call i8* @foo(i8* %B, i1 false)
+  call i8* @test1(i8* %B, i1 false)
   ret i8* null
 cond_false:
 ; CHECK: cond_false
   call void @use(i8* %A, i8* %B)
-; CHECK: tail call void @use(i8* %A.tr, i8* %B)
+; CHECK: call void @use(i8* %A.tr, i8* %B)
+  call void @boring()
+; CHECK: tail call void @boring()
   ret i8* null
 ; CHECK: ret i8* null
 }
+
+; PR14143
+define void @test2(i8* %a, i8* %b) {
+; CHECK: @test2
+; CHECK-NOT: tail call
+; CHECK: ret void
+  %c = alloca [100 x i8], align 16
+  %tmp = bitcast [100 x i8]* %c to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %b, i8* %tmp, i64 100, i32 1, i1 false)
+  ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)