blob: f1f5c71a93ab86750b414e92370d0b749b9fafca [file] [log] [blame]
; RUN: opt < %s -gvn -enable-load-pre -S | FileCheck %s
; This testcase assumed we'll PRE the load into %for.cond, but we don't actually
; verify that doing so is safe. If there didn't _happen_ to be a load in
; %for.end, we would actually be lengthening the execution on some paths, and
; we were never actually checking that case. Now we actually do perform some
; conservative checking to make sure we don't make paths longer, but we don't
; currently get this case, which we got lucky on previously.
; Now that that faulty assumption is corrected, test that we DON'T incorrectly
; hoist the load. Doing the right thing for the wrong reasons is still a bug.
@p = external global i32
define i32 @f(i32 %n) nounwind {
br label %for.cond
for.cond: ; preds =, %entry
%i.0 = phi i32 [ 0, %entry ], [, ] ; <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
; CHECK: for.body:
; CHECK-NEXT: %tmp3 = load i32* @p
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
; CHECK: for.body.for.end_crit_edge:
for.body.for.end_crit_edge: ; preds = %for.body
br label %for.end ; preds = %for.body = 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