From a5ddb59a1319ccd23844c74809a64bc4d88f59d1 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 22 Apr 2008 21:40:39 +0000 Subject: Start doing the significantly useful part of jump threading: handle cases where a comparison has a phi input and that phi is a constant. For example, stuff like: Threading edge through bool from 'bb2149' to 'bb2231' with cost: 1, across block: bb2237: ; preds = %bb2231, %bb2149 %tmp2328.rle = phi i32 [ %tmp2232, %bb2231 ], [ %tmp2232439, %bb2149 ] ; [#uses=2] %done.0 = phi i32 [ %done.2, %bb2231 ], [ 0, %bb2149 ] ; [#uses=1] %tmp2239 = icmp eq i32 %done.0, 0 ; [#uses=1] br i1 %tmp2239, label %bb2231, label %bb2327 or bb38.i298: ; preds = %bb33.i295, %bb1693 %tmp39.i296.rle = phi %struct.ibox* [ null, %bb1693 ], [ %tmp39.i296.rle1109, %bb33.i295 ] ; <%struct.ibox*> [#uses=2] %minspan.1.i291.reg2mem.1 = phi i32 [ 32000, %bb1693 ], [ %minspan.0.i288, %bb33.i295 ] ; [#uses=1] %tmp40.i297 = icmp eq %struct.ibox* %tmp39.i296.rle, null ; [#uses=1] br i1 %tmp40.i297, label %implfeeds.exit311, label %bb43.i301 This triggers thousands of times in spec. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50110 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/JumpThreading/compare.ll | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 test/Transforms/JumpThreading/compare.ll (limited to 'test') diff --git a/test/Transforms/JumpThreading/compare.ll b/test/Transforms/JumpThreading/compare.ll new file mode 100644 index 0000000..cbada56 --- /dev/null +++ b/test/Transforms/JumpThreading/compare.ll @@ -0,0 +1,30 @@ +; There should be no phi nodes left. +; RUN: llvm-as < %s | opt -jump-threading -simplifycfg -mem2reg | llvm-dis | not grep {phi i32} + +declare i32 @f1() +declare i32 @f2() +declare void @f3() + +define i32 @test(i1 %cond) { + br i1 %cond, label %T1, label %F1 + +T1: + %v1 = call i32 @f1() + br label %Merge + +F1: + %v2 = call i32 @f2() + br label %Merge + +Merge: + %B = phi i32 [%v1, %T1], [12, %F1] + %A = icmp ne i32 %B, 42 + br i1 %A, label %T2, label %F2 + +T2: + call void @f3() + ret i32 1 + +F2: + ret i32 0 +} -- cgit v1.1