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llvm-project/polly/test/Simplify/overwritten_loadbetween.ll

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[Simplify] Remove writes that are overwritten. Remove memory writes that are overwritten by later writes. This works for StoreInsts: store double 21.0, double* %A store double 42.0, double* %A scalar writes at the end of a statement and mixes of these. Multiple writes can be the result of DeLICM, which might map multiple writes to the same location when it knows that these do no conflict (for instance because they write the same value). Such writes interfere with pattern-matched optimization such as gemm and may not get removed by other LLVM passes after code generation. Differential Revision: https://reviews.llvm.org/D33142 llvm-svn: 302986
2017-05-13 19:49:34 +08:00
; RUN: opt %loadPolly -polly-simplify -analyze < %s | FileCheck -match-full-lines %s
[Polly][NewPM] Port Simplify to the new pass manager Reviewed By: Meinersbur Differential Revision: https://reviews.llvm.org/D87328
2020-09-09 05:09:03 +08:00
; RUN: opt %loadPolly "-passes=scop(print<polly-simplify>)" -disable-output -aa-pipeline=basic-aa < %s | FileCheck -match-full-lines %s
[Simplify] Remove writes that are overwritten. Remove memory writes that are overwritten by later writes. This works for StoreInsts: store double 21.0, double* %A store double 42.0, double* %A scalar writes at the end of a statement and mixes of these. Multiple writes can be the result of DeLICM, which might map multiple writes to the same location when it knows that these do no conflict (for instance because they write the same value). Such writes interfere with pattern-matched optimization such as gemm and may not get removed by other LLVM passes after code generation. Differential Revision: https://reviews.llvm.org/D33142 llvm-svn: 302986
2017-05-13 19:49:34 +08:00
;
; Do not remove overwrites when the value is read before.
;
; for (int j = 0; j < n; j += 1) {
;body:
; A[0] = 21.0;
; val = A[0];
; A[0] = 42.0;
;
;user:
; B[0] = val;
; }
;
define void @overwritten(i32 %n, double* noalias nonnull %A, double* noalias nonnull %B) {
entry:
br label %for
for:
%j = phi i32 [0, %entry], [%j.inc, %inc]
%j.cmp = icmp slt i32 %j, %n
br i1 %j.cmp, label %body, label %exit
body:
store double 21.0, double* %A
%val = load double, double* %A
store double 42.0, double* %A
br label %user
user:
store double %val, double* %B
br label %inc
inc:
%j.inc = add nuw nsw i32 %j, 1
br label %for
exit:
br label %return
return:
ret void
}
; CHECK: SCoP could not be simplified