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llvm-mirror/test/CodeGen/AArch64/arm64-long-shift.ll
Geoff Berry 33474b29b1 [AArch64] Take advantage of variable shift/rotate amount implicit mod operation.
Summary:
Optimize code generated for variable shifts/rotates by taking advantage
of the implicit and/mod done on the variable shift amount register.

Resolves bug 27582 and bug 37421.

Reviewers: t.p.northover, qcolombet, MatzeB, javed.absar

Subscribers: rengolin, kristof.beyls, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D46844

llvm-svn: 333214
2018-05-24 18:29:42 +00:00

59 lines
2.0 KiB
LLVM

; RUN: llc < %s -mtriple=arm64-eabi -mcpu=cyclone | FileCheck %s
define i128 @shl(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: shl:
; CHECK: neg [[REV_SHIFT:x[0-9]+]], x2
; CHECK: lsr [[LO_FOR_HI_NORMAL:x[0-9]+]], x0, [[REV_SHIFT]]
; CHECK: cmp x2, #0
; CHECK: csel [[LO_FOR_HI:x[0-9]+]], xzr, [[LO_FOR_HI_NORMAL]], eq
; CHECK: lsl [[HI_FOR_HI:x[0-9]+]], x1, x2
; CHECK: orr [[HI_NORMAL:x[0-9]+]], [[LO_FOR_HI]], [[HI_FOR_HI]]
; CHECK: lsl [[HI_BIG_SHIFT:x[0-9]+]], x0, x2
; CHECK: sub [[EXTRA_SHIFT:x[0-9]+]], x2, #64
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x1, [[HI_BIG_SHIFT]], [[HI_NORMAL]], ge
; CHECK: csel x0, xzr, [[HI_BIG_SHIFT]], ge
; CHECK: ret
%shl = shl i128 %r, %s
ret i128 %shl
}
define i128 @ashr(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: ashr:
; CHECK: neg [[REV_SHIFT:x[0-9]+]], x2
; CHECK: lsl [[HI_FOR_LO_NORMAL:x[0-9]+]], x1, [[REV_SHIFT]]
; CHECK: cmp x2, #0
; CHECK: csel [[HI_FOR_LO:x[0-9]+]], xzr, [[HI_FOR_LO_NORMAL]], eq
; CHECK: lsr [[LO_FOR_LO:x[0-9]+]], x0, x2
; CHECK: orr [[LO_NORMAL:x[0-9]+]], [[LO_FOR_LO]], [[HI_FOR_LO]]
; CHECK: asr [[LO_BIG_SHIFT:x[0-9]+]], x1, x2
; CHECK: sub [[EXTRA_SHIFT:x[0-9]+]], x2, #64
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x0, [[LO_BIG_SHIFT]], [[LO_NORMAL]], ge
; CHECK: asr [[BIGSHIFT_HI:x[0-9]+]], x1, #63
; CHECK: csel x1, [[BIGSHIFT_HI]], [[LO_BIG_SHIFT]], ge
; CHECK: ret
%shr = ashr i128 %r, %s
ret i128 %shr
}
define i128 @lshr(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: lshr:
; CHECK: neg [[REV_SHIFT:x[0-9]+]], x2
; CHECK: lsl [[HI_FOR_LO_NORMAL:x[0-9]+]], x1, [[REV_SHIFT]]
; CHECK: cmp x2, #0
; CHECK: csel [[HI_FOR_LO:x[0-9]+]], xzr, [[HI_FOR_LO_NORMAL]], eq
; CHECK: lsr [[LO_FOR_LO:x[0-9]+]], x0, x2
; CHECK: orr [[LO_NORMAL:x[0-9]+]], [[LO_FOR_LO]], [[HI_FOR_LO]]
; CHECK: lsr [[LO_BIG_SHIFT:x[0-9]+]], x1, x2
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x0, [[LO_BIG_SHIFT]], [[LO_NORMAL]], ge
; CHECK: csel x1, xzr, [[LO_BIG_SHIFT]], ge
; CHECK: ret
%shr = lshr i128 %r, %s
ret i128 %shr
}