llvm-for-llvmta/test/CodeGen/NVPTX/pow2_mask_cmp.ll

20 lines
644 B
LLVM

; RUN: llc -march=nvptx -verify-machineinstrs < %s | FileCheck %s
; Tests the following pattern:
; (X & 8) != 0 --> (X & 8) >> 3
; This produces incorrect code in general when boolean false is
; represented as a negative one. There is however a special
; case when the type has a bitsize of 1, for which the false
; value will be identical regardless of the boolean representation.
; Check that the optimization triggers in this case.
; CHECK-LABEL: @pow2_mask_cmp
; CHECK: bfe.u32 {{%r[0-9]+}}, {{%r[0-9]+}}, 3, 1
define i32 @pow2_mask_cmp(i32 %x) {
%a = and i32 %x, 8
%cmp = icmp ne i32 %a, 0
%r = zext i1 %cmp to i32
ret i32 %r
}