From 416d91c799a8d30f190d63a803ab82aed8a11635 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 18 Feb 2008 06:12:38 +0000
Subject: optimize away stackrestore calls that have no intervening alloca or
call.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47258 91177308-0d34-0410-b5e6-96231b3b80d8
---
test/Transforms/InstCombine/stacksaverestore.ll | 43 +++++++++++++++++++++++--
1 file changed, 40 insertions(+), 3 deletions(-)
(limited to 'test')
diff --git a/test/Transforms/InstCombine/stacksaverestore.ll b/test/Transforms/InstCombine/stacksaverestore.ll
index 29001a0..c82a425 100644
--- a/test/Transforms/InstCombine/stacksaverestore.ll
+++ b/test/Transforms/InstCombine/stacksaverestore.ll
@@ -1,4 +1,7 @@
-; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {call.*stackrestore}
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {call.*stackrestore} | count 1
+
+declare i8* @llvm.stacksave()
+declare void @llvm.stackrestore(i8*)
;; Test that llvm.stackrestore is removed when possible.
define i32* @test1(i32 %P) {
@@ -13,7 +16,41 @@ define void @test2(i8* %X) {
ret void
}
-declare i8* @llvm.stacksave()
+define void @foo(i32 %size) nounwind {
+entry:
+ %tmp118124 = icmp sgt i32 %size, 0 ; <i1> [#uses=1]
+ br i1 %tmp118124, label %bb.preheader, label %return
-declare void @llvm.stackrestore(i8*)
+bb.preheader: ; preds = %entry
+ %tmp25 = add i32 %size, -1 ; <i32> [#uses=1]
+ %tmp125 = icmp slt i32 %size, 1 ; <i1> [#uses=1]
+ %smax = select i1 %tmp125, i32 1, i32 %size ; <i32> [#uses=1]
+ br label %bb
+
+bb: ; preds = %bb, %bb.preheader
+ %i.0.reg2mem.0 = phi i32 [ 0, %bb.preheader ], [ %indvar.next, %bb ] ; <i32> [#uses=2]
+ %tmp = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
+ %tmp23 = alloca i8, i32 %size ; <i8*> [#uses=2]
+ %tmp27 = getelementptr i8* %tmp23, i32 %tmp25 ; <i8*> [#uses=1]
+ store i8 0, i8* %tmp27, align 1
+ %tmp28 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
+ %tmp52 = alloca i8, i32 %size ; <i8*> [#uses=1]
+ %tmp53 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
+ %tmp77 = alloca i8, i32 %size ; <i8*> [#uses=1]
+ %tmp78 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
+ %tmp102 = alloca i8, i32 %size ; <i8*> [#uses=1]
+ call void @bar( i32 %i.0.reg2mem.0, i8* %tmp23, i8* %tmp52, i8* %tmp77, i8* %tmp102, i32 %size ) nounwind
+ call void @llvm.stackrestore( i8* %tmp78 )
+ call void @llvm.stackrestore( i8* %tmp53 )
+ call void @llvm.stackrestore( i8* %tmp28 )
+ call void @llvm.stackrestore( i8* %tmp )
+ %indvar.next = add i32 %i.0.reg2mem.0, 1 ; <i32> [#uses=2]
+ %exitcond = icmp eq i32 %indvar.next, %smax ; <i1> [#uses=1]
+ br i1 %exitcond, label %return, label %bb
+
+return: ; preds = %bb, %entry
+ ret void
+}
+
+declare void @bar(i32, i8*, i8*, i8*, i8*, i32)
--
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