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llvm-mirror/test/CodeGen/AArch64/fast-isel-branch-cond-split.ll
Matthias Braun 096ba9c487 AArch64FastISel: Use cbz/cbnz to branch on i1
In the case of a conditional branch without a preceding cmp we used to emit
a "and; cmp; b.eq/b.ne" sequence, use tbz/tbnz instead.

Differential Revision: http://reviews.llvm.org/D15122

llvm-svn: 254621
2015-12-03 17:19:58 +00:00

91 lines
1.9 KiB
LLVM

; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -fast-isel-abort=1 -verify-machineinstrs < %s | FileCheck %s
; CHECK-LABEL: test_or
; CHECK: cbnz w0, {{LBB[0-9]+_2}}
; CHECK: cbz w1, {{LBB[0-9]+_1}}
define i64 @test_or(i32 %a, i32 %b) {
bb1:
%0 = icmp eq i32 %a, 0
%1 = icmp eq i32 %b, 0
%or.cond = or i1 %0, %1
br i1 %or.cond, label %bb3, label %bb4, !prof !0
bb3:
ret i64 0
bb4:
%2 = call i64 @bar()
ret i64 %2
}
; CHECK-LABEL: test_and
; CHECK: cbz w0, {{LBB[0-9]+_2}}
; CHECK: cbnz w1, {{LBB[0-9]+_3}}
define i64 @test_and(i32 %a, i32 %b) {
bb1:
%0 = icmp ne i32 %a, 0
%1 = icmp ne i32 %b, 0
%or.cond = and i1 %0, %1
br i1 %or.cond, label %bb4, label %bb3, !prof !1
bb3:
ret i64 0
bb4:
%2 = call i64 @bar()
ret i64 %2
}
; If the branch is unpredictable, don't add another branch.
; CHECK-LABEL: test_or_unpredictable
; CHECK: cmp w0, #0
; CHECK-NEXT: cset w8, eq
; CHECK-NEXT: cmp w1, #0
; CHECK-NEXT: cset w9, eq
; CHECK-NEXT: orr w8, w8, w9
; CHECK-NEXT: tbnz w8, #0,
define i64 @test_or_unpredictable(i32 %a, i32 %b) {
bb1:
%0 = icmp eq i32 %a, 0
%1 = icmp eq i32 %b, 0
%or.cond = or i1 %0, %1
br i1 %or.cond, label %bb3, label %bb4, !unpredictable !2
bb3:
ret i64 0
bb4:
%2 = call i64 @bar()
ret i64 %2
}
; CHECK-LABEL: test_and_unpredictable
; CHECK: cmp w0, #0
; CHECK-NEXT: cset w8, ne
; CHECK-NEXT: cmp w1, #0
; CHECK-NEXT: cset w9, ne
; CHECK-NEXT: and w8, w8, w9
; CHECK-NEXT: tbz w8, #0,
define i64 @test_and_unpredictable(i32 %a, i32 %b) {
bb1:
%0 = icmp ne i32 %a, 0
%1 = icmp ne i32 %b, 0
%or.cond = and i1 %0, %1
br i1 %or.cond, label %bb4, label %bb3, !unpredictable !2
bb3:
ret i64 0
bb4:
%2 = call i64 @bar()
ret i64 %2
}
declare i64 @bar()
!0 = !{!"branch_weights", i32 5128, i32 32}
!1 = !{!"branch_weights", i32 1024, i32 4136}
!2 = !{}