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llvm-mirror/test/CodeGen/AArch64/arm64-long-shift.ll
Tim Northover c434b24d59 AArch64: fix 128-bit shifts
We mustn't introduce a shift of exactly 64-bits for any inputs, since that's an
UNDEF value (and worse, it's not what you want with the natural Arch64
implementation).

The generated code is pretty horrific, but I couldn't come up with an obviously
better alternative (if the amount is constant EXTR could help). Turns out
128-bit shifts are just nasty.

rdar://22491037

llvm-svn: 254475
2015-12-02 00:33:54 +00:00

66 lines
2.4 KiB
LLVM

; RUN: llc < %s -march=arm64 -mcpu=cyclone | FileCheck %s
define i128 @shl(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: shl:
; CHECK: orr w[[SIXTY_FOUR:[0-9]+]], wzr, #0x40
; CHECK: sub [[REV_SHIFT:x[0-9]+]], x[[SIXTY_FOUR]], 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: sub [[EXTRA_SHIFT:x[0-9]+]], x2, #64
; CHECK: lsl [[HI_BIG_SHIFT:x[0-9]+]], x0, [[EXTRA_SHIFT]]
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x1, [[HI_BIG_SHIFT]], [[HI_NORMAL]], ge
; CHECK: lsl [[SMALLSHIFT_LO:x[0-9]+]], x0, x2
; CHECK: csel x0, xzr, [[SMALLSHIFT_LO]], ge
; CHECK: ret
%shl = shl i128 %r, %s
ret i128 %shl
}
define i128 @ashr(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: ashr:
; CHECK: orr w[[SIXTY_FOUR:[0-9]+]], wzr, #0x40
; CHECK: sub [[REV_SHIFT:x[0-9]+]], x[[SIXTY_FOUR]], 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: sub [[EXTRA_SHIFT:x[0-9]+]], x2, #64
; CHECK: asr [[LO_BIG_SHIFT:x[0-9]+]], x1, [[EXTRA_SHIFT]]
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x0, [[LO_BIG_SHIFT]], [[LO_NORMAL]], ge
; CHECK: asr [[SMALLSHIFT_HI:x[0-9]+]], x1, x2
; CHECK: asr [[BIGSHIFT_HI:x[0-9]+]], x1, #63
; CHECK: csel x1, [[BIGSHIFT_HI]], [[SMALLSHIFT_HI]], ge
; CHECK: ret
%shr = ashr i128 %r, %s
ret i128 %shr
}
define i128 @lshr(i128 %r, i128 %s) nounwind readnone {
; CHECK-LABEL: lshr:
; CHECK: orr w[[SIXTY_FOUR:[0-9]+]], wzr, #0x40
; CHECK: sub [[REV_SHIFT:x[0-9]+]], x[[SIXTY_FOUR]], 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: sub [[EXTRA_SHIFT:x[0-9]+]], x2, #64
; CHECK: lsr [[LO_BIG_SHIFT:x[0-9]+]], x1, [[EXTRA_SHIFT]]
; CHECK: cmp [[EXTRA_SHIFT]], #0
; CHECK: csel x0, [[LO_BIG_SHIFT]], [[LO_NORMAL]], ge
; CHECK: lsr [[SMALLSHIFT_HI:x[0-9]+]], x1, x2
; CHECK: csel x1, xzr, [[SMALLSHIFT_HI]], ge
; CHECK: ret
%shr = lshr i128 %r, %s
ret i128 %shr
}