llvm-capstone/polly/test/DeLICM/skip_multiaccess.ll
Michael Kruse 19cd61dc11 [DeLICM] Do not try to map to multiple array elements.
Add check and skip when the store used to determine the target accesses
multiple array elements. Only a single array location should for
mapping the scalar. Having multiple creates problems when deciding which
element to load from. While MemoryAccess::getAddressFunction() should
select just one of them, other problems arise in code that assumes
that there is just one target element per statement instance.

This fixes llvm.org/PR34989

This also reverts r313902 which fixed llvm.org/PR34485 also caused by
a non-functional target array element. This patch avoids the situation
to occur in the first place.

llvm-svn: 316432
2017-10-24 13:05:24 +00:00

71 lines
1.7 KiB
LLVM

; RUN: opt %loadPolly -polly-delicm -pass-remarks-missed=polly-delicm -disable-output < %s 2>&1 | FileCheck %s
;
; llvm.org/PR34485
; llvm.org/PR34989
;
; The memset causes the array A to be divided into i8-sized subelements.
; The the regular store then writes multiple of these subelements, which
; we do not support currently.
;
; void func(double *A) {
; memset(A, 0, 4);
; for (int j = 0; j < 2; j += 1) { /* outer */
; double phi = 0.0;
; for (int i = 0; i < 4; i += 1) /* reduction */
; phi += 4.2;
; A[j] = phi;
; }
; }
declare void @llvm.memset.p0f64.i64(double* nocapture, i8, i64, i32, i1)
define void @func(double* noalias nonnull %A) {
entry:
br label %outer.for
outer.for:
%j = phi i32 [0, %entry], [%j.inc, %outer.inc]
call void @llvm.memset.p0f64.i64(double* %A, i8 0, i64 4, i32 1, i1 false)
%j.cmp = icmp slt i32 %j, 2
br i1 %j.cmp, label %reduction.for, label %outer.exit
reduction.for:
%i = phi i32 [0, %outer.for], [%i.inc, %reduction.inc]
%phi = phi double [0.0, %outer.for], [%add, %reduction.inc]
%i.cmp = icmp slt i32 %i, 4
br i1 %i.cmp, label %body, label %reduction.exit
body:
%add = fadd double %phi, 4.2
br label %reduction.inc
reduction.inc:
%i.inc = add nuw nsw i32 %i, 1
br label %reduction.for
reduction.exit:
%A_idx = getelementptr inbounds double, double* %A, i32 %j
store double %phi, double* %A_idx
br label %outer.inc
outer.inc:
%j.inc = add nuw nsw i32 %j, 1
br label %outer.for
outer.exit:
br label %return
return:
ret void
}
; CHECK: skipped possible mapping target because it writes more than one element