[polly] r252424 - [FIX] Carefully simplify assumptions in the presence of error blocks
Johannes Doerfert via llvm-commits
llvm-commits at lists.llvm.org
Sun Nov 8 12:16:39 PST 2015
Author: jdoerfert
Date: Sun Nov 8 14:16:39 2015
New Revision: 252424
URL: http://llvm.org/viewvc/llvm-project?rev=252424&view=rev
Log:
[FIX] Carefully simplify assumptions in the presence of error blocks
If a SCoP contains error blocks we cannot use the domain constraints
to simplify the assumptions as the domain is already influenced by the
assumptions we took. Before this patch we did that and some assumptions
became self-fulfilling as they were implied by the domain constraints.
Added:
polly/trunk/test/Isl/Ast/runtime_context_with_error_blocks.ll
Modified:
polly/trunk/include/polly/ScopInfo.h
polly/trunk/lib/Analysis/ScopInfo.cpp
polly/trunk/test/ScopInfo/non-pure-function-calls-causes-dead-blocks.ll
Modified: polly/trunk/include/polly/ScopInfo.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/ScopInfo.h?rev=252424&r1=252423&r2=252424&view=diff
==============================================================================
--- polly/trunk/include/polly/ScopInfo.h (original)
+++ polly/trunk/include/polly/ScopInfo.h Sun Nov 8 14:16:39 2015
@@ -1033,6 +1033,9 @@ private:
/// @brief True if the underlying region has a single exiting block.
bool HasSingleExitEdge;
+ /// @brief Flag to remember if the SCoP contained an error block or not.
+ bool HasErrorBlock;
+
/// Max loop depth.
unsigned MaxLoopDepth;
@@ -1517,6 +1520,9 @@ public:
/// @brief Align the parameters in the statement to the scop context
void realignParams();
+ /// @brief Return true if the SCoP contained at least one error block.
+ bool hasErrorBlock() const { return HasErrorBlock; }
+
/// @brief Return true if the underlying region has a single exiting block.
bool hasSingleExitEdge() const { return HasSingleExitEdge; }
Modified: polly/trunk/lib/Analysis/ScopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopInfo.cpp?rev=252424&r1=252423&r2=252424&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopInfo.cpp (original)
+++ polly/trunk/lib/Analysis/ScopInfo.cpp Sun Nov 8 14:16:39 2015
@@ -1663,8 +1663,18 @@ void Scop::realignParams() {
static __isl_give isl_set *
simplifyAssumptionContext(__isl_take isl_set *AssumptionContext,
const Scop &S) {
- isl_set *DomainParameters = isl_union_set_params(S.getDomains());
- AssumptionContext = isl_set_gist_params(AssumptionContext, DomainParameters);
+ // If we modelt all blocks in the SCoP that have side effects we can simplify
+ // the context with the constraints that are needed for anything to be
+ // executed at all. However, if we have error blocks in the SCoP we already
+ // assumed some parameter combinations cannot occure and removed them from the
+ // domains, thus we cannot use the remaining domain to simplify the
+ // assumptions.
+ if (!S.hasErrorBlock()) {
+ isl_set *DomainParameters = isl_union_set_params(S.getDomains());
+ AssumptionContext =
+ isl_set_gist_params(AssumptionContext, DomainParameters);
+ }
+
AssumptionContext = isl_set_gist_params(AssumptionContext, S.getContext());
return AssumptionContext;
}
@@ -1918,8 +1928,10 @@ void Scop::buildDomainsWithBranchConstra
// the predecessors and can therefor look at the domain of a error block.
// That allows us to generate the assumptions needed for them not to be
// executed at runtime.
- if (containsErrorBlock(RN, getRegion(), LI, DT))
+ if (containsErrorBlock(RN, getRegion(), LI, DT)) {
+ HasErrorBlock = true;
continue;
+ }
BasicBlock *BB = getRegionNodeBasicBlock(RN);
TerminatorInst *TI = BB->getTerminator();
@@ -2443,9 +2455,10 @@ Scop::Scop(Region &R, AccFuncMapType &Ac
isl_ctx *Context, unsigned MaxLoopDepth)
: LI(LI), DT(DT), SE(&ScalarEvolution), SD(SD), R(R),
AccFuncMap(AccFuncMap), IsOptimized(false),
- HasSingleExitEdge(R.getExitingBlock()), MaxLoopDepth(MaxLoopDepth),
- IslCtx(Context), Context(nullptr), Affinator(this),
- AssumedContext(nullptr), BoundaryContext(nullptr), Schedule(nullptr) {}
+ HasSingleExitEdge(R.getExitingBlock()), HasErrorBlock(false),
+ MaxLoopDepth(MaxLoopDepth), IslCtx(Context), Context(nullptr),
+ Affinator(this), AssumedContext(nullptr), BoundaryContext(nullptr),
+ Schedule(nullptr) {}
void Scop::init(AliasAnalysis &AA) {
buildContext();
Added: polly/trunk/test/Isl/Ast/runtime_context_with_error_blocks.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/Isl/Ast/runtime_context_with_error_blocks.ll?rev=252424&view=auto
==============================================================================
--- polly/trunk/test/Isl/Ast/runtime_context_with_error_blocks.ll (added)
+++ polly/trunk/test/Isl/Ast/runtime_context_with_error_blocks.ll Sun Nov 8 14:16:39 2015
@@ -0,0 +1,65 @@
+; RUN: opt %loadPolly -polly-code-generator=isl -polly-ast -analyze < %s | FileCheck %s
+;
+; Verify we do not simplify the runtime check to "true" due to the domain
+; constraints as the test contains an error block that influenced the domains
+; already.
+;
+; CHECK: if (this <= -1 || this >= 1)
+;
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+%"class.std::ctype" = type <{ %"class.std::locale::facet.base", [4 x i8], %struct.__locale_struct*, i8, [7 x i8], i32*, i32*, i16*, i8, [256 x i8], [256 x i8], i8, [6 x i8] }>
+%"class.std::locale::facet.base" = type <{ i32 (...)**, i32 }>
+%struct.__locale_struct = type { [13 x %struct.__locale_data*], i16*, i32*, i32*, [13 x i8*] }
+%struct.__locale_data = type opaque
+
+$_ZNKSt5ctypeIcE5widenEc = comdat any
+
+; Function Attrs: uwtable
+define weak_odr signext i8 @_ZNKSt5ctypeIcE5widenEc(%"class.std::ctype"* %this, i8 signext %__c) #0 comdat align 2 {
+entry:
+ br label %entry.split
+
+entry.split: ; preds = %entry
+ %_M_widen_ok = getelementptr inbounds %"class.std::ctype", %"class.std::ctype"* %this, i64 0, i32 8
+ %0 = load i8, i8* %_M_widen_ok, align 8, !tbaa !1
+ %tobool = icmp eq i8 %0, 0
+ br i1 %tobool, label %if.end, label %if.then
+
+if.then: ; preds = %entry.split
+ %idxprom = zext i8 %__c to i64
+ %arrayidx = getelementptr inbounds %"class.std::ctype", %"class.std::ctype"* %this, i64 0, i32 9, i64 %idxprom
+ %1 = load i8, i8* %arrayidx, align 1, !tbaa !7
+ br label %return
+
+if.end: ; preds = %entry.split
+ tail call void @_ZNKSt5ctypeIcE13_M_widen_initEv(%"class.std::ctype"* %this)
+ %2 = bitcast %"class.std::ctype"* %this to i8 (%"class.std::ctype"*, i8)***
+ %vtable = load i8 (%"class.std::ctype"*, i8)**, i8 (%"class.std::ctype"*, i8)*** %2, align 8, !tbaa !8
+ %vfn = getelementptr inbounds i8 (%"class.std::ctype"*, i8)*, i8 (%"class.std::ctype"*, i8)** %vtable, i64 6
+ %3 = load i8 (%"class.std::ctype"*, i8)*, i8 (%"class.std::ctype"*, i8)** %vfn, align 8
+ %call = tail call signext i8 %3(%"class.std::ctype"* %this, i8 signext %__c)
+ br label %return
+
+return: ; preds = %if.end, %if.then
+ %retval.0 = phi i8 [ %1, %if.then ], [ %call, %if.end ]
+ ret i8 %retval.0
+}
+
+declare void @_ZNKSt5ctypeIcE13_M_widen_initEv(%"class.std::ctype"*) #1
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 3.8.0 (http://llvm.org/git/clang.git 97e5436f69f1bfa7f3e7fd2ecd80cdee0ae95bef)"}
+!1 = !{!2, !4, i64 56}
+!2 = !{!"_ZTSSt5ctypeIcE", !3, i64 16, !6, i64 24, !3, i64 32, !3, i64 40, !3, i64 48, !4, i64 56, !4, i64 57, !4, i64 313, !4, i64 569}
+!3 = !{!"any pointer", !4, i64 0}
+!4 = !{!"omnipotent char", !5, i64 0}
+!5 = !{!"Simple C/C++ TBAA"}
+!6 = !{!"bool", !4, i64 0}
+!7 = !{!4, !4, i64 0}
+!8 = !{!9, !9, i64 0}
+!9 = !{!"vtable pointer", !5, i64 0}
Modified: polly/trunk/test/ScopInfo/non-pure-function-calls-causes-dead-blocks.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopInfo/non-pure-function-calls-causes-dead-blocks.ll?rev=252424&r1=252423&r2=252424&view=diff
==============================================================================
--- polly/trunk/test/ScopInfo/non-pure-function-calls-causes-dead-blocks.ll (original)
+++ polly/trunk/test/ScopInfo/non-pure-function-calls-causes-dead-blocks.ll Sun Nov 8 14:16:39 2015
@@ -31,13 +31,12 @@
; timer_stop();
; }
;
-; The assumed context is empty because all statements are executed only
-; if timeit != 0. This is due to the fact that they are not "reached"
-; by the error blocks that are executed for timeit == 0.
+; The assumed context should not be empty even though all statements are
+; executed only if timeit != 0.
;
; CHECK: Region: %entry.split---%if.end.20
; CHECK: Assumed Context:
-; CHECK-NEXT: [timeit, N] -> { : }
+; CHECK-NEXT: [timeit, N] -> { : timeit = 0 }
; CHECK: Statements {
; CHECK-NOT: Stmt_if_then_split
; CHECK: Stmt_for_body
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