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[LoopAccessAnalysis][SVE] Bail out for scalable vectors
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The supplied test case, reduced from real world code, crashes with a
'Invalid size request on a scalable vector.' error.

Since it's similar in spirit to an existing LAA test, rename the file to
generalize it to both.

Differential Revision: https://reviews.llvm.org/D114155
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peterwaller-arm committed Nov 24, 2021
1 parent a12192c commit 787b66e
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9 changes: 8 additions & 1 deletion llvm/lib/Analysis/LoopAccessAnalysis.cpp
Expand Up @@ -1057,6 +1057,12 @@ int64_t llvm::getPtrStride(PredicatedScalarEvolution &PSE, Type *AccessTy,
assert(Ty->isPointerTy() && "Unexpected non-ptr");
assert(!AccessTy->isAggregateType() && "Bad stride - Not a pointer to a scalar type");

if (isa<ScalableVectorType>(AccessTy)) {
LLVM_DEBUG(dbgs() << "LAA: Bad stride - Scalable object: " << *AccessTy
<< "\n");
return 0;
}

const SCEV *PtrScev = replaceSymbolicStrideSCEV(PSE, StridesMap, Ptr);

const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PtrScev);
Expand Down Expand Up @@ -1117,7 +1123,8 @@ int64_t llvm::getPtrStride(PredicatedScalarEvolution &PSE, Type *AccessTy,
}

auto &DL = Lp->getHeader()->getModule()->getDataLayout();
int64_t Size = DL.getTypeAllocSize(AccessTy);
TypeSize AllocSize = DL.getTypeAllocSize(AccessTy);
int64_t Size = AllocSize.getFixedSize();
const APInt &APStepVal = C->getAPInt();

// Huge step value - give up.
Expand Down

This file was deleted.

@@ -0,0 +1,62 @@
; RUN: opt -loop-load-elim -mtriple=aarch64 -mattr=+sve -S -debug < %s 2>&1 | FileCheck %s
; REQUIRES: asserts

; Regression tests verifying "assumption that TypeSize is not scalable" and
; "Invalid size request on a scalable vector." are not produced by
; -load-loop-elim (this would cause the test to fail because opt would exit with
; a non-zero exit status).

; No output checked for this one, but causes a fatal error if the regression is present.

define void @regression_test_get_gep_induction_operand_typesize_warning(i64 %n, <vscale x 4 x i32>* %a) {
entry:
br label %loop.body

loop.body:
%0 = phi i64 [ 0, %entry ], [ %1, %loop.body ]
%idx = getelementptr <vscale x 4 x i32>, <vscale x 4 x i32>* %a, i64 %0
store <vscale x 4 x i32> zeroinitializer, <vscale x 4 x i32>* %idx
%1 = add i64 %0, 1
%2 = icmp eq i64 %1, %n
br i1 %2, label %loop.end, label %loop.body

loop.end:
ret void
}

; CHECK-LABEL: LAA: Found a loop in regression_test_loop_access_scalable_typesize
; CHECK: LAA: Bad stride - Scalable object:
define void @regression_test_loop_access_scalable_typesize(<vscale x 16 x i8>* %input_ptr) {
entry:
br label %vector.body
vector.body:
%ind_ptr = phi <vscale x 16 x i8>* [ %next_ptr, %vector.body ], [ %input_ptr, %entry ]
%ind = phi i64 [ %next, %vector.body ], [ 0, %entry ]
%ld = load <vscale x 16 x i8>, <vscale x 16 x i8>* %ind_ptr, align 16
store <vscale x 16 x i8> zeroinitializer, <vscale x 16 x i8>* %ind_ptr, align 16
%next_ptr = getelementptr inbounds <vscale x 16 x i8>, <vscale x 16 x i8>* %ind_ptr, i64 1
%next = add i64 %ind, 1
%cond = icmp ult i64 %next, 1024
br i1 %cond, label %end, label %vector.body
end:
ret void
}

; CHECK-LABEL: LAA: Found a loop in regression_test_loop_access_scalable_typesize_nonscalable_object
; CHECK: LAA: Bad stride - Scalable object:
define void @regression_test_loop_access_scalable_typesize_nonscalable_object(i8* %input_ptr) {
entry:
br label %vector.body
vector.body:
%ind_ptr = phi i8* [ %next_ptr, %vector.body ], [ %input_ptr, %entry ]
%ind = phi i64 [ %next, %vector.body ], [ 0, %entry ]
%scalable_ptr = bitcast i8* %ind_ptr to <vscale x 16 x i8>*
%ld = load <vscale x 16 x i8>, <vscale x 16 x i8>* %scalable_ptr, align 16
store <vscale x 16 x i8> zeroinitializer, <vscale x 16 x i8>* %scalable_ptr, align 16
%next_ptr = getelementptr inbounds i8, i8* %ind_ptr, i64 1
%next = add i64 %ind, 1
%cond = icmp ult i64 %next, 1024
br i1 %cond, label %end, label %vector.body
end:
ret void
}

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