51 lines
1.5 KiB
LLVM
51 lines
1.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
|
|
; RUN: opt < %s -instcombine -S | FileCheck %s
|
|
|
|
; Result of left shifting a non-negative integer
|
|
; with nsw flag should also be non-negative
|
|
define i1 @test_shift_nonnegative(i32 %a) {
|
|
; CHECK-LABEL: @test_shift_nonnegative(
|
|
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], -1
|
|
; CHECK-NEXT: ret i1 [[CMP]]
|
|
;
|
|
%b = lshr i32 %a, 2
|
|
%shift = shl nsw i32 %b, 3
|
|
%cmp = icmp sge i32 %shift, 0
|
|
ret i1 %cmp
|
|
}
|
|
|
|
; Result of left shifting a negative integer with
|
|
; nsw flag should also be negative
|
|
define i1 @test_shift_negative(i32 %a, i32 %b) {
|
|
; CHECK-LABEL: @test_shift_negative(
|
|
; CHECK-NEXT: ret i1 true
|
|
;
|
|
%c = or i32 %a, -2147483648
|
|
%d = and i32 %b, 7
|
|
%shift = shl nsw i32 %c, %d
|
|
%cmp = icmp slt i32 %shift, 0
|
|
ret i1 %cmp
|
|
}
|
|
|
|
; If sign bit is a known zero, it cannot be a known one.
|
|
; This test should not crash opt. The shift produces poison.
|
|
define i32 @test_no_sign_bit_conflict1(i1 %b) {
|
|
; CHECK-LABEL: @test_no_sign_bit_conflict1(
|
|
; CHECK-NEXT: ret i32 undef
|
|
;
|
|
%sel = select i1 %b, i32 8193, i32 8192
|
|
%mul = shl nsw i32 %sel, 18
|
|
ret i32 %mul
|
|
}
|
|
|
|
; If sign bit is a known one, it cannot be a known zero.
|
|
; This test should not crash opt. The shift produces poison.
|
|
define i32 @test_no_sign_bit_conflict2(i1 %b) {
|
|
; CHECK-LABEL: @test_no_sign_bit_conflict2(
|
|
; CHECK-NEXT: ret i32 undef
|
|
;
|
|
%sel = select i1 %b, i32 -8193, i32 -8194
|
|
%mul = shl nsw i32 %sel, 18
|
|
ret i32 %mul
|
|
}
|