[CodeGen][IfCvt] Don't re-ifcvt blocks with unanalyzable terminators.
If we couldn't analyze its terminator (i.e., it's an indirectbr, or some
other weirdness), we can't safely re-if-convert a predicated block,
because we can't tell whether the predicated terminator can
fallthrough (it does).
Currently, we would completely ignore the fallthrough successor. In
the added testcase, this means we used to generate:
...
@ %entry:
cmp r5, #21
ittt ne
@ %cc1f:
cmpne r7, #42
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %cc1t:
...
Whereas the successor of %cc1f was originally %bb1.
With the fix, we get the correct:
...
@ %entry:
cmp r5, #21
itt eq
@ %cc1t:
streq.w r5, [r11]
moveq pc, r0
@ %cc1f:
cmp r7, #42
itt ne
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %bb1:
...
rdar://20192768
Differential Revision: http://reviews.llvm.org/D8509
llvm-svn: 232872
2015-03-21 09:23:15 +08:00
|
|
|
; RUN: llc < %s -mtriple thumbv7s-apple-darwin -asm-verbose=false | FileCheck %s
|
2015-12-01 13:29:22 +08:00
|
|
|
; RUN: llc < %s -mtriple thumbv7s-apple-darwin -asm-verbose=false -print-machineinstrs=if-converter 2>&1 | FileCheck --check-prefix=CHECK-PROB %s
|
[CodeGen][IfCvt] Don't re-ifcvt blocks with unanalyzable terminators.
If we couldn't analyze its terminator (i.e., it's an indirectbr, or some
other weirdness), we can't safely re-if-convert a predicated block,
because we can't tell whether the predicated terminator can
fallthrough (it does).
Currently, we would completely ignore the fallthrough successor. In
the added testcase, this means we used to generate:
...
@ %entry:
cmp r5, #21
ittt ne
@ %cc1f:
cmpne r7, #42
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %cc1t:
...
Whereas the successor of %cc1f was originally %bb1.
With the fix, we get the correct:
...
@ %entry:
cmp r5, #21
itt eq
@ %cc1t:
streq.w r5, [r11]
moveq pc, r0
@ %cc1f:
cmp r7, #42
itt ne
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %bb1:
...
rdar://20192768
Differential Revision: http://reviews.llvm.org/D8509
llvm-svn: 232872
2015-03-21 09:23:15 +08:00
|
|
|
|
|
|
|
declare i32 @foo(i32)
|
|
|
|
declare i8* @bar(i32, i8*, i8*)
|
|
|
|
|
|
|
|
; Verify that we don't try to iteratively re-ifconvert a block with a
|
|
|
|
; (predicated) indirectbr terminator.
|
|
|
|
; If we do, we would ignore its fallthrough successor.
|
|
|
|
|
|
|
|
|
|
|
|
; CHECK-LABEL: test:
|
|
|
|
; CHECK: cmp {{.*}}, #21
|
|
|
|
; CHECK-NEXT: itt eq
|
|
|
|
; CHECK-NEXT: streq.w
|
|
|
|
; CHECK-NEXT: moveq pc
|
|
|
|
; CHECK-NEXT: LBB{{[0-9_]+}}:
|
|
|
|
; CHECK-NEXT: cmp {{.*}}, #42
|
|
|
|
; CHECK-NEXT: itt ne
|
|
|
|
; CHECK-NEXT: strne.w
|
|
|
|
; CHECK-NEXT: movne pc
|
|
|
|
; CHECK-NEXT: Ltmp
|
|
|
|
; CHECK-NEXT: LBB0_2:
|
|
|
|
; CHECK-NEXT: movw r0, #1234
|
|
|
|
; CHECK-NEXT: b [[FOOCALL:LBB[0-9_]+]]
|
|
|
|
; CHECK-NEXT: Ltmp
|
|
|
|
; CHECK-NEXT: LBB{{[0-9_]+}}:
|
|
|
|
; CHECK-NEXT: movw r0, #4567
|
|
|
|
; CHECK-NEXT: [[FOOCALL]]:
|
2016-05-11 03:17:47 +08:00
|
|
|
; CHECK-NEXT: bl _foo
|
2015-09-19 04:22:41 +08:00
|
|
|
;
|
2015-12-01 13:29:22 +08:00
|
|
|
; CHECK-PROB: BB#0:
|
|
|
|
; CHECK-PROB: Successors according to CFG: BB#1({{[0-9a-fx/= ]+}}50.00%) BB#2({{[0-9a-fx/= ]+}}25.00%) BB#4({{[0-9a-fx/= ]+}}25.00%)
|
|
|
|
; CHECK-PROB: BB#1:
|
|
|
|
; CHECK-PROB: Successors according to CFG: BB#2({{[0-9a-fx/= ]+}}75.00%) BB#4({{[0-9a-fx/= ]+}}25.00%)
|
[CodeGen][IfCvt] Don't re-ifcvt blocks with unanalyzable terminators.
If we couldn't analyze its terminator (i.e., it's an indirectbr, or some
other weirdness), we can't safely re-if-convert a predicated block,
because we can't tell whether the predicated terminator can
fallthrough (it does).
Currently, we would completely ignore the fallthrough successor. In
the added testcase, this means we used to generate:
...
@ %entry:
cmp r5, #21
ittt ne
@ %cc1f:
cmpne r7, #42
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %cc1t:
...
Whereas the successor of %cc1f was originally %bb1.
With the fix, we get the correct:
...
@ %entry:
cmp r5, #21
itt eq
@ %cc1t:
streq.w r5, [r11]
moveq pc, r0
@ %cc1f:
cmp r7, #42
itt ne
@ %cc2t:
strne.w r5, [r8]
movne pc, r10
@ %bb1:
...
rdar://20192768
Differential Revision: http://reviews.llvm.org/D8509
llvm-svn: 232872
2015-03-21 09:23:15 +08:00
|
|
|
|
|
|
|
define i32 @test(i32 %a, i32 %a2, i32* %p, i32* %p2) {
|
|
|
|
entry:
|
|
|
|
%dst1 = call i8* @bar(i32 1, i8* blockaddress(@test, %bb1), i8* blockaddress(@test, %bb2))
|
|
|
|
%dst2 = call i8* @bar(i32 2, i8* blockaddress(@test, %bb1), i8* blockaddress(@test, %bb2))
|
|
|
|
%dst3 = call i8* @bar(i32 3, i8* blockaddress(@test, %bb1), i8* blockaddress(@test, %bb2))
|
|
|
|
%cc1 = icmp eq i32 %a, 21
|
|
|
|
br i1 %cc1, label %cc1t, label %cc1f
|
|
|
|
|
|
|
|
cc1t:
|
|
|
|
store i32 %a, i32* %p
|
|
|
|
indirectbr i8* %dst3, [label %bb1, label %bb2]
|
|
|
|
|
|
|
|
cc1f:
|
|
|
|
%cc2 = icmp ne i32 %a2, 42
|
|
|
|
br i1 %cc2, label %cc2t, label %bb1
|
|
|
|
cc2t:
|
|
|
|
store i32 %a, i32* %p2
|
|
|
|
indirectbr i8* %dst1, [label %bb1, label %bb2]
|
|
|
|
|
|
|
|
bb1:
|
|
|
|
%ret_bb1 = call i32 @foo(i32 1234)
|
|
|
|
ret i32 %ret_bb1
|
|
|
|
bb2:
|
|
|
|
%ret_bb2 = call i32 @foo(i32 4567)
|
|
|
|
ret i32 %ret_bb2
|
|
|
|
}
|