llvm-6502/test/CodeGen/SystemZ/shift-10.ll
Richard Sandiford f9a5e40b90 Replace sra with srl if a single sign bit is required
E.g. (and (sra (i32 x) 31) 2) -> (and (srl (i32 x) 30) 2).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192884 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-17 11:16:57 +00:00

79 lines
1.8 KiB
LLVM

; Test compound shifts.
;
; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
; Test a shift right followed by a sign extension. This can use two shifts.
define i64 @f1(i32 %a) {
; CHECK-LABEL: f1:
; CHECK: sllg [[REG:%r[0-5]]], %r2, 62
; CHECK: srag %r2, [[REG]], 63
; CHECK: br %r14
%shr = lshr i32 %a, 1
%trunc = trunc i32 %shr to i1
%ext = sext i1 %trunc to i64
ret i64 %ext
}
; ...and again with the highest shift count.
define i64 @f2(i32 %a) {
; CHECK-LABEL: f2:
; CHECK: sllg [[REG:%r[0-5]]], %r2, 32
; CHECK: srag %r2, [[REG]], 63
; CHECK: br %r14
%shr = lshr i32 %a, 31
%trunc = trunc i32 %shr to i1
%ext = sext i1 %trunc to i64
ret i64 %ext
}
; Test a left shift that of an extended right shift in a case where folding
; is possible.
define i64 @f3(i32 %a) {
; CHECK-LABEL: f3:
; CHECK: risbg %r2, %r2, 27, 181, 9
; CHECK: br %r14
%shr = lshr i32 %a, 1
%ext = zext i32 %shr to i64
%shl = shl i64 %ext, 10
%and = and i64 %shl, 137438952960
ret i64 %and
}
; ...and again with a larger right shift.
define i64 @f4(i32 %a) {
; CHECK-LABEL: f4:
; CHECK: risbg %r2, %r2, 30, 158, 3
; CHECK: br %r14
%shr = lshr i32 %a, 30
%ext = sext i32 %shr to i64
%shl = shl i64 %ext, 33
%and = and i64 %shl, 8589934592
ret i64 %and
}
; Repeat the previous test in a case where all bits outside the
; bottom 3 matter.
define i64 @f5(i32 %a) {
; CHECK-LABEL: f5:
; CHECK: risbg %r2, %r2, 29, 158, 3
; CHECK: lhi %r2, 7
; CHECK: br %r14
%shr = lshr i32 %a, 30
%ext = sext i32 %shr to i64
%shl = shl i64 %ext, 33
%or = or i64 %shl, 7
ret i64 %or
}
; Test that SRA gets replaced with SRL if the sign bit is the only one
; that matters.
define i64 @f6(i64 %a) {
; CHECK-LABEL: f6:
; CHECK: risbg %r2, %r2, 55, 183, 19
; CHECK: br %r14
%shl = shl i64 %a, 10
%shr = ashr i64 %shl, 60
%and = and i64 %shr, 256
ret i64 %and
}