llvm-mirror/test/Transforms/InstCombine/bcopy.ll
David Bolvansky 39fe272c25 [InstCombine] Transform bcopy to memmove
bcopy is still widely used mainly for network apps. Sadly, LLVM has no optimizations for bcopy, but there are some for memmove. 
Since bcopy == memmove, it is profitable to transform bcopy to memmove and use current optimizations for memmove for free here.

llvm-svn: 373537
2019-10-02 22:49:20 +00:00

26 lines
966 B
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
declare void @bcopy(i8* nocapture readonly, i8* nocapture, i32)
define void @bcopy_memmove(i8* nocapture readonly %a, i8* nocapture %b) {
; CHECK-LABEL: @bcopy_memmove(
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i8* [[A:%.*]] to i64*
; CHECK-NEXT: [[TMP2:%.*]] = bitcast i8* [[B:%.*]] to i64*
; CHECK-NEXT: [[TMP3:%.*]] = load i64, i64* [[TMP1]], align 1
; CHECK-NEXT: store i64 [[TMP3]], i64* [[TMP2]], align 1
; CHECK-NEXT: ret void
;
tail call void @bcopy(i8* %a, i8* %b, i32 8)
ret void
}
define void @bcopy_memmove2(i8* nocapture readonly %a, i8* nocapture %b, i32 %len) {
; CHECK-LABEL: @bcopy_memmove2(
; CHECK-NEXT: call void @llvm.memmove.p0i8.p0i8.i32(i8* align 1 [[B:%.*]], i8* align 1 [[A:%.*]], i32 [[LEN:%.*]], i1 false)
; CHECK-NEXT: ret void
;
tail call void @bcopy(i8* %a, i8* %b, i32 %len)
ret void
}