1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
| ; RUN: llc -o - -verify-machineinstrs %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@data = external global [3 x i32], align 4
@store = external global i32, align 4
; %else1 and %then2 end up lowering to identical blocks. These blocks should be
; merged during tail-merging.
; CHECK-LABEL: merge_identical_blocks
; CHECK: movl $data+4
; CHECK-NOT: movl $data+4
; CHECK: retq
define void @merge_identical_blocks(i1 %a, i1 %b) {
entry:
br label %if1
if1: ; predfs = %entry
br i1 %a, label %else1, label %if2
else1: ; preds = %if1
%ptr.else1 = getelementptr inbounds [3 x i32], [3 x i32]* @data, i64 0, i32 1
br label %phi_join
if2: ; preds = %if1
br i1 %b, label %then2, label %else2
then2: ; preds = %if2
%ptr.then2 = getelementptr inbounds [3 x i32], [3 x i32]* @data, i64 0, i32 1
br label %phi_join
else2: ; preds = %if2
%ptr.else2 = getelementptr inbounds [3 x i32], [3 x i32]* @data, i64 0, i32 2
br label %phi_join
phi_join: ; preds = %else1, %then2, %else2
%val.ptr = phi i32* [ %ptr.else1, %else1 ], [ %ptr.then2, %then2 ], [ %ptr.else2, %else2 ]
%val = load i32, i32* %val.ptr, align 4
store i32 %val, i32* @store, align 4
ret void
}
|