36cb33bbca
The patch add branch hint for AtomicExpandImpl::expandAtomicCmpXchg, For
example: in PowerPC, it support branch hint as
```
loop:
lwarx r6,0,r3 # load and reserve
cmpw r4,r6 #1st 2 operands equal? bne- exit #skip if not
bne- exit #skip if not
stwcx. r5,0,r3 #store new value if still res’ved bne- loop #loop if lost reservation
bne- loop #loop if lost reservation
exit:
mr r4,r6 #return value from storage
```
`-` hints not taken,
`+` hints taken,
56 lines
1.8 KiB
LLVM
56 lines
1.8 KiB
LLVM
; RUN: llc < %s -mtriple=armv7-apple-ios -verify-machineinstrs | FileCheck %s
|
|
|
|
define void @test_cmpxchg_weak(ptr %addr, i32 %desired, i32 %new) {
|
|
; CHECK-LABEL: test_cmpxchg_weak:
|
|
; CHECK-NEXT: %bb.0:
|
|
; CHECK-NEXT: ldrex [[LOADED:r[0-9]+]], [r0]
|
|
; CHECK-NEXT: cmp [[LOADED]], r1
|
|
; CHECK-NEXT: bne [[LDFAILBB:LBB[0-9]+_[0-9]+]]
|
|
; CHECK-NEXT: %bb.1:
|
|
; CHECK-NEXT: dmb ish
|
|
; CHECK-NEXT: strex [[SUCCESS:r[0-9]+]], r2, [r0]
|
|
; CHECK-NEXT: cmp [[SUCCESS]], #0
|
|
; CHECK-NEXT: bne [[FAILBB:LBB[0-9]+_[0-9]+]]
|
|
; CHECK-NEXT: %bb.2:
|
|
; CHECK-NEXT: dmb ish
|
|
; CHECK-NEXT: str r3, [r0]
|
|
; CHECK-NEXT: bx lr
|
|
; CHECK-NEXT: [[LDFAILBB]]:
|
|
; CHECK-NEXT: clrex
|
|
; CHECK-NEXT: [[FAILBB]]:
|
|
; CHECK-NEXT: str r3, [r0]
|
|
; CHECK-NEXT: bx lr
|
|
;
|
|
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new seq_cst monotonic
|
|
%oldval = extractvalue { i32, i1 } %pair, 0
|
|
store i32 %oldval, ptr %addr
|
|
ret void
|
|
}
|
|
|
|
define i1 @test_cmpxchg_weak_to_bool(i32, ptr %addr, i32 %desired, i32 %new) {
|
|
; CHECK-LABEL: test_cmpxchg_weak_to_bool:
|
|
; CHECK-NEXT: %bb.0:
|
|
; CHECK-NEXT: ldrex [[LOADED:r[0-9]+]], [r1]
|
|
; CHECK-NEXT: cmp [[LOADED]], r2
|
|
; CHECK-NEXT: bne [[LDFAILBB:LBB[0-9]+_[0-9]+]]
|
|
; CHECK-NEXT: %bb.1:
|
|
; CHECK-NEXT: dmb ish
|
|
; CHECK-NEXT: strex [[SUCCESS:r[0-9]+]], r3, [r1]
|
|
; CHECK-NEXT: cmp [[SUCCESS]], #0
|
|
; CHECK-NEXT: bne [[FAILBB:LBB[0-9]+_[0-9]+]]
|
|
; CHECK-NEXT: %bb.2:
|
|
; CHECK-NEXT: mov r0, #1
|
|
; CHECK-NEXT: dmb ish
|
|
; CHECK-NEXT: bx lr
|
|
; CHECK-NEXT: [[LDFAILBB]]:
|
|
; CHECK-NEXT: clrex
|
|
; CHECK-NEXT: [[FAILBB]]:
|
|
; CHECK-NEXT: mov r0, #0
|
|
; CHECK-NEXT: bx lr
|
|
;
|
|
|
|
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new seq_cst monotonic
|
|
%success = extractvalue { i32, i1 } %pair, 1
|
|
ret i1 %success
|
|
}
|