llvm-6502/test/Transforms/GVN/pre-single-pred.ll
Owen Anderson 88554df4a2 Be more aggressive in doing LoadPRE by tracing backwards when a block only has
a single predecessor.

Patch by Jakub Staszak.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72661 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-31 09:03:40 +00:00

33 lines
1023 B
LLVM

; RUN: llvm-as < %s | opt -gvn -enable-load-pre | llvm-dis | not grep {tmp3 = load}
define i32 @f(i32* nocapture %p, i32 %n) nounwind {
entry:
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%i.0 = phi i32 [ 0, %entry ], [ %indvar.next, %for.inc ] ; <i32> [#uses=2]
%cmp = icmp slt i32 %i.0, %n ; <i1> [#uses=1]
br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
for.cond.for.end_crit_edge: ; preds = %for.cond
br label %for.end
for.body: ; preds = %for.cond
%tmp3 = load i32* %p ; <i32> [#uses=1]
%dec = add i32 %tmp3, -1 ; <i32> [#uses=2]
store i32 %dec, i32* %p
%cmp6 = icmp slt i32 %dec, 0 ; <i1> [#uses=1]
br i1 %cmp6, label %for.body.for.end_crit_edge, label %for.inc
for.body.for.end_crit_edge: ; preds = %for.body
br label %for.end
for.inc: ; preds = %for.body
%indvar.next = add i32 %i.0, 1 ; <i32> [#uses=1]
br label %for.cond
for.end: ; preds = %for.body.for.end_crit_edge, %for.cond.for.end_crit_edge
%tmp9 = load i32* %p ; <i32> [#uses=1]
ret i32 %tmp9
}