urem-via-udiv-mul-sub.ll
3.64 KB
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt %s -instcombine -S | FileCheck %s
; Fold
; x - ((x / y) * y)
; to
; x % y
; Also,
; ((x / y) * y)
; can then be simplified to
; x - (x % y)
declare void @use8(i8)
declare void @use2xi8(<2 x i8>)
define i8 @t0_basic(i8 %x, i8 %y) {
; CHECK-LABEL: @t0_basic(
; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT: [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret i8 [[REM]]
;
%div = udiv i8 %x, %y
call void @use8(i8 %div)
%roundXdownToMultipleOfY = mul i8 %div, %y
%rem = sub i8 %x, %roundXdownToMultipleOfY
ret i8 %rem
}
define <2 x i8> @t1_vector(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @t1_vector(
; CHECK-NEXT: [[DIV:%.*]] = udiv <2 x i8> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use2xi8(<2 x i8> [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul <2 x i8> [[DIV]], [[Y]]
; CHECK-NEXT: [[REM:%.*]] = sub <2 x i8> [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret <2 x i8> [[REM]]
;
%div = udiv <2 x i8> %x, %y
call void @use2xi8(<2 x i8> %div)
%roundXdownToMultipleOfY = mul <2 x i8> %div, %y
%rem = sub <2 x i8> %x, %roundXdownToMultipleOfY
ret <2 x i8> %rem
}
; Extra use
define i8 @t4_extrause(i8 %x, i8 %y) {
; CHECK-LABEL: @t4_extrause(
; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[ROUNDXDOWNTOMULTIPLEOFY]])
; CHECK-NEXT: [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret i8 [[REM]]
;
%div = udiv i8 %x, %y
call void @use8(i8 %div)
%roundXdownToMultipleOfY = mul i8 %div, %y
call void @use8(i8 %roundXdownToMultipleOfY)
%rem = sub i8 %x, %roundXdownToMultipleOfY
ret i8 %rem
}
; Commutativity
declare i8 @gen8()
define i8 @t5_commutative(i8 %x) {
; CHECK-LABEL: @t5_commutative(
; CHECK-NEXT: [[Y:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[Y]], [[DIV]]
; CHECK-NEXT: [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret i8 [[REM]]
;
%y = call i8 @gen8()
%div = udiv i8 %x, %y
call void @use8(i8 %div)
%roundXdownToMultipleOfY = mul i8 %y, %div ; swapped
%rem = sub i8 %x, %roundXdownToMultipleOfY
ret i8 %rem
}
; Negative tests
define i8 @n6_different_x(i8 %x0, i8 %x1, i8 %y) {
; CHECK-LABEL: @n6_different_x(
; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[X0:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT: [[REM:%.*]] = sub i8 [[X1:%.*]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret i8 [[REM]]
;
%div = udiv i8 %x0, %y
call void @use8(i8 %div)
%roundXdownToMultipleOfY = mul i8 %div, %y
%rem = sub i8 %x1, %roundXdownToMultipleOfY
ret i8 %rem
}
define i8 @n6_different_y(i8 %x, i8 %y0, i8 %y1) {
; CHECK-LABEL: @n6_different_y(
; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y0:%.*]]
; CHECK-NEXT: call void @use8(i8 [[DIV]])
; CHECK-NEXT: [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y1:%.*]]
; CHECK-NEXT: [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT: ret i8 [[REM]]
;
%div = udiv i8 %x, %y0
call void @use8(i8 %div)
%roundXdownToMultipleOfY = mul i8 %div, %y1
%rem = sub i8 %x, %roundXdownToMultipleOfY
ret i8 %rem
}