Fix CountCodeReductionForAlloca to more accurately represent what SROA can and

can't handle. Also don't produce non-zero results for things which won't be
transformed by SROA at all just because we saw the loads/stores before we saw
the use of the address.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148536 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 44 insertions, 0 deletions

diff --git a/test/Transforms/Inline/alloca-bonus.ll b/test/Transforms/Inline/alloca-bonus.ll
new file mode 100644
index 0000000..2587ae1
--- /dev/null
+++ b/test/Transforms/Inline/alloca-bonus.ll
@@ -0,0 +1,44 @@
+; RUN: opt -inline < %s -S -o - -inline-threshold=8 | FileCheck %s
+
+declare void @llvm.lifetime.start(i64 %size, i8* nocapture %ptr)
+
+@glbl = external global i32
+
+define void @outer1() {
+; CHECK: @outer1
+; CHECK-NOT: call void @inner1
+  %ptr = alloca i32
+  call void @inner1(i32* %ptr)
+  ret void
+}
+
+define void @inner1(i32 *%ptr) {
+  %A = load i32* %ptr
+  store i32 0, i32* %ptr
+  %C = getelementptr i32* %ptr, i32 0
+  %D = getelementptr i32* %ptr, i32 1
+  %E = bitcast i32* %ptr to i8*
+  %F = select i1 false, i32* %ptr, i32* @glbl
+  call void @llvm.lifetime.start(i64 0, i8* %E)
+  ret void
+}
+
+define void @outer2() {
+; CHECK: @outer2
+; CHECK: call void @inner2
+  %ptr = alloca i32
+  call void @inner2(i32* %ptr)
+  ret void
+}
+
+; %D poisons this call, scalar-repl can't handle that instruction.
+define void @inner2(i32 *%ptr) {
+  %A = load i32* %ptr
+  store i32 0, i32* %ptr
+  %C = getelementptr i32* %ptr, i32 0
+  %D = getelementptr i32* %ptr, i32 %A
+  %E = bitcast i32* %ptr to i8*
+  %F = select i1 false, i32* %ptr, i32* @glbl
+  call void @llvm.lifetime.start(i64 0, i8* %E)
+  ret void
+}