llvm/test/Transforms/InstCombine/udiv_select_to_select_shift.ll
2016-11-11 23:12:46 +00:00

22 lines
729 B
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; Test that this transform works:
; udiv X, (Select Cond, C1, C2) --> Select Cond, (shr X, C1), (shr X, C2)
define i64 @test(i64 %X, i1 %Cond ) {
; CHECK-LABEL: @test(
; CHECK-NEXT: [[QUOTIENT1:%.*]] = lshr i64 %X, 4
; CHECK-NEXT: [[QUOTIENT2:%.*]] = lshr i64 %X, 3
; CHECK-NEXT: [[SUM:%.*]] = add nuw nsw i64 [[QUOTIENT1]], [[QUOTIENT2]]
; CHECK-NEXT: ret i64 [[SUM]]
;
%divisor1 = select i1 %Cond, i64 16, i64 8
%quotient1 = udiv i64 %X, %divisor1
%divisor2 = select i1 %Cond, i64 8, i64 0
%quotient2 = udiv i64 %X, %divisor2
%sum = add i64 %quotient1, %quotient2
ret i64 %sum
}