[polly] r310350 - [Polly] [PPCGCodeGeneration] Handle failing of invariant load hoisting gracefully.
Siddharth Bhat via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 8 05:00:59 PDT 2017
Author: bollu
Date: Tue Aug 8 05:00:59 2017
New Revision: 310350
URL: http://llvm.org/viewvc/llvm-project?rev=310350&view=rev
Log:
[Polly] [PPCGCodeGeneration] Handle failing of invariant load hoisting gracefully.
To do this, we replicate what `CodeGeneration` does. We expose
`markNodeUnreachable` from `CodeGeneration` to `PPCGCodeGeneration`.
Differential Revision: https://reviews.llvm.org/D36457
Added:
polly/trunk/test/GPGPU/failing-invariant-load-handling.ll
Modified:
polly/trunk/include/polly/CodeGen/CodeGeneration.h
polly/trunk/lib/CodeGen/CodeGeneration.cpp
polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp
Modified: polly/trunk/include/polly/CodeGen/CodeGeneration.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/CodeGen/CodeGeneration.h?rev=310350&r1=310349&r2=310350&view=diff
==============================================================================
--- polly/trunk/include/polly/CodeGen/CodeGeneration.h (original)
+++ polly/trunk/include/polly/CodeGen/CodeGeneration.h Tue Aug 8 05:00:59 2017
@@ -12,6 +12,7 @@
#ifndef POLLY_CODEGENERATION_H
#define POLLY_CODEGENERATION_H
+#include "IRBuilder.h"
#include "polly/Config/config.h"
#include "polly/ScopPass.h"
#include "isl/map.h"
@@ -25,6 +26,12 @@ enum VectorizerChoice {
};
extern VectorizerChoice PollyVectorizerChoice;
+/// Mark a basic block unreachable.
+///
+/// Marks the basic block @p Block unreachable by equipping it with an
+/// UnreachableInst.
+void markBlockUnreachable(BasicBlock &Block, PollyIRBuilder &Builder);
+
struct CodeGenerationPass : public PassInfoMixin<CodeGenerationPass> {
PreservedAnalyses run(Scop &S, ScopAnalysisManager &SAM,
ScopStandardAnalysisResults &AR, SPMUpdater &U);
Modified: polly/trunk/lib/CodeGen/CodeGeneration.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/CodeGen/CodeGeneration.cpp?rev=310350&r1=310349&r2=310350&view=diff
==============================================================================
--- polly/trunk/lib/CodeGen/CodeGeneration.cpp (original)
+++ polly/trunk/lib/CodeGen/CodeGeneration.cpp Tue Aug 8 05:00:59 2017
@@ -54,6 +54,20 @@ static cl::opt<bool>
cl::desc("Add run-time performance monitoring"), cl::Hidden,
cl::init(false), cl::ZeroOrMore, cl::cat(PollyCategory));
+namespace polly {
+/// Mark a basic block unreachable.
+///
+/// Marks the basic block @p Block unreachable by equipping it with an
+/// UnreachableInst.
+void markBlockUnreachable(BasicBlock &Block, PollyIRBuilder &Builder) {
+ auto *OrigTerminator = Block.getTerminator();
+ Builder.SetInsertPoint(OrigTerminator);
+ Builder.CreateUnreachable();
+ OrigTerminator->eraseFromParent();
+}
+
+} // namespace polly
+
namespace {
static void verifyGeneratedFunction(Scop &S, Function &F, IslAstInfo &AI) {
@@ -86,17 +100,6 @@ static void fixRegionInfo(Function &F, R
}
}
-/// Mark a basic block unreachable.
-///
-/// Marks the basic block @p Block unreachable by equipping it with an
-/// UnreachableInst.
-static void markBlockUnreachable(BasicBlock &Block, PollyIRBuilder &Builder) {
- auto *OrigTerminator = Block.getTerminator();
- Builder.SetInsertPoint(OrigTerminator);
- Builder.CreateUnreachable();
- OrigTerminator->eraseFromParent();
-}
-
/// Remove all lifetime markers (llvm.lifetime.start, llvm.lifetime.end) from
/// @R.
///
Modified: polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp?rev=310350&r1=310349&r2=310350&view=diff
==============================================================================
--- polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp (original)
+++ polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp Tue Aug 8 05:00:59 2017
@@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//
#include "polly/CodeGen/PPCGCodeGeneration.h"
+#include "polly/CodeGen/CodeGeneration.h"
#include "polly/CodeGen/IslAst.h"
#include "polly/CodeGen/IslNodeBuilder.h"
#include "polly/CodeGen/Utils.h"
@@ -3373,7 +3374,6 @@ public:
// TODO: Handle LICM
auto SplitBlock = StartBlock->getSinglePredecessor();
Builder.SetInsertPoint(SplitBlock->getTerminator());
- NodeBuilder.addParameters(S->getContext().release());
isl_ast_build *Build = isl_ast_build_alloc(S->getIslCtx());
isl_ast_expr *Condition = IslAst::buildRunCondition(*S, Build);
@@ -3383,17 +3383,34 @@ public:
// preload invariant loads. Note: This should happen before the RTC
// because the RTC may depend on values that are invariant load hoisted.
- if (!NodeBuilder.preloadInvariantLoads())
- report_fatal_error("preloading invariant loads failed in function: " +
- S->getFunction().getName() +
- " | Scop Region: " + S->getNameStr());
+ if (!NodeBuilder.preloadInvariantLoads()) {
+ DEBUG(dbgs() << "preloading invariant loads failed in function: " +
+ S->getFunction().getName() +
+ " | Scop Region: " + S->getNameStr());
+ // adjust the dominator tree accordingly.
+ auto *ExitingBlock = StartBlock->getUniqueSuccessor();
+ assert(ExitingBlock);
+ auto *MergeBlock = ExitingBlock->getUniqueSuccessor();
+ assert(MergeBlock);
+ polly::markBlockUnreachable(*StartBlock, Builder);
+ polly::markBlockUnreachable(*ExitingBlock, Builder);
+ auto *ExitingBB = S->getExitingBlock();
+ assert(ExitingBB);
+
+ DT->changeImmediateDominator(MergeBlock, ExitingBB);
+ DT->eraseNode(ExitingBlock);
+ isl_ast_expr_free(Condition);
+ isl_ast_node_free(Root);
+ } else {
- Value *RTC = NodeBuilder.createRTC(Condition);
- Builder.GetInsertBlock()->getTerminator()->setOperand(0, RTC);
+ NodeBuilder.addParameters(S->getContext().release());
+ Value *RTC = NodeBuilder.createRTC(Condition);
+ Builder.GetInsertBlock()->getTerminator()->setOperand(0, RTC);
- Builder.SetInsertPoint(&*StartBlock->begin());
+ Builder.SetInsertPoint(&*StartBlock->begin());
- NodeBuilder.create(Root);
+ NodeBuilder.create(Root);
+ }
/// In case a sequential kernel has more surrounding loops as any parallel
/// kernel, the SCoP is probably mostly sequential. Hence, there is no
Added: polly/trunk/test/GPGPU/failing-invariant-load-handling.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/GPGPU/failing-invariant-load-handling.ll?rev=310350&view=auto
==============================================================================
--- polly/trunk/test/GPGPU/failing-invariant-load-handling.ll (added)
+++ polly/trunk/test/GPGPU/failing-invariant-load-handling.ll Tue Aug 8 05:00:59 2017
@@ -0,0 +1,56 @@
+; RUN: opt %loadPolly < %s -analyze -polly-scops -polly-process-unprofitable -polly-invariant-load-hoisting | FileCheck %s -check-prefix=SCOPS
+; RUN: opt %loadPolly -S < %s -polly-codegen-ppcg -polly-process-unprofitable -polly-invariant-load-hoisting | FileCheck %s -check-prefix=CODEGEN
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n8:16:32-S64"
+
+%S = type { i32, i32, [12 x %L] }
+%L = type { i32, i32, double, i32, i32, i32, i32, i32 }
+
+define void @test(%S* %cpi, i1 %b) {
+; SCOPS-LABEL: Region: %if.then14---%exit
+; SCOPS: Invariant Accesses: {
+; SCOPS-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 0]
+; SCOPS-NEXT: [l2, l1] -> { Stmt_for_body_i[i0] -> MemRef_cpi[0, 0] };
+; SCOPS-NEXT: Execution Context: [l2, l1] -> { : }
+; SCOPS-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 0]
+; SCOPS-NEXT: [l2, l1] -> { Stmt_for_body_lr_ph_i[] -> MemRef_cpi[0, 1] };
+; SCOPS-NEXT: Execution Context: [l2, l1] -> { : l2 > 0 }
+; SCOPS-NEXT: }
+; SCOPS: Arrays {
+; SCOPS-NEXT: i32 MemRef_cpi[*][(10 * %l1)]; // Element size 4
+; SCOPS-NEXT: }
+
+; Check that we gracefully handle failing invariant loads.
+; This test case is taken from:
+; test/Isl/CodeGen/invariant-load-dimension.ll
+
+; FIXME: Figure out how to actually generate code for this loop.
+; CODEGEN-NOT: LLVM ERROR: preloading invariant loads failed in function
+
+entry:
+ %nt = getelementptr inbounds %S, %S* %cpi, i32 0, i32 1
+ br i1 %b, label %if.then14, label %exit
+
+if.then14:
+ %ns = getelementptr inbounds %S, %S* %cpi, i32 0, i32 0
+ %l0 = load i32, i32* %ns, align 8
+ %cmp12.i = icmp sgt i32 %l0, 0
+ br i1 %cmp12.i, label %for.body.lr.ph.i, label %exit
+
+for.body.lr.ph.i:
+ %l1 = load i32, i32* %nt, align 4
+ br label %for.body.i
+
+for.body.i:
+ %phi = phi i32 [ 0, %for.body.lr.ph.i ], [ %inc, %for.body.i ]
+ %mul.i163 = mul nsw i32 %phi, %l1
+ %cv = getelementptr inbounds %S, %S* %cpi, i32 0, i32 2, i32 %mul.i163, i32 0
+ store i32 0, i32* %cv, align 8
+ %inc = add nuw nsw i32 %phi, 1
+ %l2 = load i32, i32* %ns, align 8
+ %cmp.i164 = icmp slt i32 %inc, %l2
+ br i1 %cmp.i164, label %for.body.i, label %exit
+
+exit:
+ ret void
+}
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