llvm/test/Transforms/LoopLoadElim/opt-size.ll
Adam Nemet a8e75884ec [LoopLoadElim] Don't allow versioning when optForSize
This was requested in the review of D16300.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259861 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-05 01:14:05 +00:00

77 lines
2.4 KiB
LLVM

; RUN: opt -basicaa -loop-load-elim -S < %s | FileCheck %s
; When optimizing for size don't eliminate in this loop because the loop would
; have to be versioned first because A and C may alias.
;
; for (unsigned i = 0; i < 100; i++) {
; A[i+1] = B[i] + 2;
; C[i] = A[i] * 2;
; }
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
; CHECK-LABEL: @f(
define void @f(i32* %A, i32* %B, i32* %C, i64 %N) optsize {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%Aidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next
%Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
%Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv
%Aidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
%b = load i32, i32* %Bidx, align 4
%a_p1 = add i32 %b, 2
store i32 %a_p1, i32* %Aidx_next, align 4
%a = load i32, i32* %Aidx, align 4
; CHECK: %c = mul i32 %a, 2
%c = mul i32 %a, 2
store i32 %c, i32* %Cidx, align 4
%exitcond = icmp eq i64 %indvars.iv.next, %N
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; Same loop but with noalias on %A and %C. In this case load-eliminate even
; with -Os.
; CHECK-LABEL: @g(
define void @g(i32* noalias %A, i32* %B, i32* noalias %C, i64 %N) optsize {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%Aidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next
%Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
%Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv
%Aidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
%b = load i32, i32* %Bidx, align 4
%a_p1 = add i32 %b, 2
store i32 %a_p1, i32* %Aidx_next, align 4
%a = load i32, i32* %Aidx, align 4
; CHECK: %c = mul i32 %store_forwarded, 2
%c = mul i32 %a, 2
store i32 %c, i32* %Cidx, align 4
%exitcond = icmp eq i64 %indvars.iv.next, %N
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}