[polly] r308971 - [PPCGCodeGeneration] Skip arrays with empty extent.
Siddharth Bhat via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 25 05:35:36 PDT 2017
Author: bollu
Date: Tue Jul 25 05:35:36 2017
New Revision: 308971
URL: http://llvm.org/viewvc/llvm-project?rev=308971&view=rev
Log:
[PPCGCodeGeneration] Skip arrays with empty extent.
Invariant load hoisted scalars, and arrays whose size we can statically compute
to be 0 do not need to be allocated as arrays.
Invariant load hoisted scalars are sent to the kernel directly as parameters.
Earlier, we used to allocate `0` bytes of memory for these because our
computation of size from `PPCGCodeGeneration::getArraySize` would result in `0`.
Now, since we don't invariant loads as arrays in PPCGCodeGeneration, this
problem does not occur anymore.
Differential Revision: https://reviews.llvm.org/D35795
Added:
polly/trunk/test/GPGPU/invariant-load-of-scalar.ll
Modified:
polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp
Modified: polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp?rev=308971&r1=308970&r2=308971&view=diff
==============================================================================
--- polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp (original)
+++ polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp Tue Jul 25 05:35:36 2017
@@ -2714,9 +2714,10 @@ public:
/// Create the arrays for @p PPCGProg.
///
/// @param PPCGProg The program to compute the arrays for.
- void createArrays(gpu_prog *PPCGProg) {
+ void createArrays(gpu_prog *PPCGProg,
+ const SmallVector<ScopArrayInfo *, 4> &ValidSAIs) {
int i = 0;
- for (auto &Array : S->arrays()) {
+ for (auto &Array : ValidSAIs) {
std::string TypeName;
raw_string_ostream OS(TypeName);
@@ -2800,11 +2801,25 @@ public:
isl_union_map_empty(isl_set_get_space(PPCGScop->context));
PPCGProg->n_stmts = std::distance(S->begin(), S->end());
PPCGProg->stmts = getStatements();
- PPCGProg->n_array = std::distance(S->array_begin(), S->array_end());
+
+ // Only consider arrays that have a non-empty extent.
+ // Otherwise, this will cause us to consider the following kinds of
+ // empty arrays:
+ // 1. Invariant loads that are represented by SAI objects.
+ // 2. Arrays with statically known zero size.
+ auto ValidSAIsRange =
+ make_filter_range(S->arrays(), [this](ScopArrayInfo *SAI) -> bool {
+ return !isl::manage(getExtent(SAI)).is_empty();
+ });
+ SmallVector<ScopArrayInfo *, 4> ValidSAIs(ValidSAIsRange.begin(),
+ ValidSAIsRange.end());
+
+ PPCGProg->n_array =
+ ValidSAIs.size(); // std::distance(S->array_begin(), S->array_end());
PPCGProg->array = isl_calloc_array(S->getIslCtx(), struct gpu_array_info,
PPCGProg->n_array);
- createArrays(PPCGProg);
+ createArrays(PPCGProg, ValidSAIs);
PPCGProg->may_persist = compute_may_persist(PPCGProg);
return PPCGProg;
Added: polly/trunk/test/GPGPU/invariant-load-of-scalar.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/GPGPU/invariant-load-of-scalar.ll?rev=308971&view=auto
==============================================================================
--- polly/trunk/test/GPGPU/invariant-load-of-scalar.ll (added)
+++ polly/trunk/test/GPGPU/invariant-load-of-scalar.ll Tue Jul 25 05:35:36 2017
@@ -0,0 +1,84 @@
+; RUN: opt %loadPolly -polly-scops -polly-invariant-load-hoisting \
+; RUN: -analyze < %s | \
+; RUN: FileCheck -check-prefix=SCOP %s
+
+; RUN: opt %loadPolly -polly-codegen-ppcg -polly-invariant-load-hoisting \
+; RUN: -S < %s | \
+; RUN: FileCheck -check-prefix=HOST-IR %s
+
+
+; RUN: opt %loadPolly -polly-codegen-ppcg -polly-invariant-load-hoisting \
+; RUN: -disable-output -polly-acc-dump-kernel-ir < %s | \
+; RUN: FileCheck -check-prefix=KERNEL-IR %s
+
+; REQUIRES: pollyacc
+
+; Check that we offload invariant loads of scalars correctly.
+
+; Check that invariant loads are present.
+; SCOP: Function: checkPrivatization
+; SCOP-NEXT: Region: %entry.split---%for.end
+; SCOP-NEXT: Max Loop Depth: 1
+; SCOP-NEXT: Invariant Accesses: {
+; SCOP-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 0]
+; SCOP-NEXT: [tmp, tmp2] -> { Stmt_entry_split[] -> MemRef_begin[0] };
+; SCOP-NEXT: Execution Context: [tmp, tmp2] -> { : }
+; SCOP-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 0]
+; SCOP-NEXT: [tmp, tmp2] -> { Stmt_for_body[i0] -> MemRef_end[0] };
+; SCOP-NEXT: Execution Context: [tmp, tmp2] -> { : }
+; SCOP-NEXT: }
+;
+
+; Check that we do not actually allocate arrays for %begin, %end, since they are
+; invariant load hoisted.
+; HOST-IR: %p_dev_array_MemRef_A = call i8* @polly_allocateMemoryForDevice(i64 %35)
+; HOST-IR-NOT: call i8* @polly_allocateMemoryForDevice
+
+; Check that we send the invariant loaded scalars as parameters to the
+; kernel function.
+; KERNEL-IR: define ptx_kernel void @FUNC_checkPrivatization_SCOP_0_KERNEL_0
+; KERNEL-IR-SAME: (i8 addrspace(1)* %MemRef_A, i32 %tmp,
+; KERNEL-IR-SAME: i32 %tmp2, i32 %polly.access.begin.load,
+; KERNEL-IR-SAME: i32 %polly.access.end.load)
+
+
+; void checkScalarPointerOffload(int A[], int *begin, int *end) {
+; for(int i = *begin; i < *end; i++) {
+; A[i] = 10;
+; }
+; }
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.12.0"
+
+define void @checkPrivatization(i32* %A, i32* %begin, i32* %end) {
+entry:
+ br label %entry.split
+
+entry.split: ; preds = %entry
+ %tmp = load i32, i32* %begin, align 4
+ %tmp21 = load i32, i32* %end, align 4
+ %cmp3 = icmp slt i32 %tmp, %tmp21
+ br i1 %cmp3, label %for.body.lr.ph, label %for.end
+
+for.body.lr.ph: ; preds = %entry.split
+ %tmp1 = sext i32 %tmp to i64
+ br label %for.body
+
+for.body: ; preds = %for.body.lr.ph, %for.body
+ %indvars.iv4 = phi i64 [ %tmp1, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv4
+ store i32 10, i32* %arrayidx, align 4
+ %indvars.iv.next = add i64 %indvars.iv4, 1
+ %tmp2 = load i32, i32* %end, align 4
+ %tmp3 = sext i32 %tmp2 to i64
+ %cmp = icmp slt i64 %indvars.iv.next, %tmp3
+ br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
+
+for.cond.for.end_crit_edge: ; preds = %for.body
+ br label %for.end
+
+for.end: ; preds = %for.cond.for.end_crit_edge, %entry.split
+ ret void
+}
+
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