[llvm] r230150 - IRCE: use SCEVs instead of llvm::Value's for intermediate
Sanjoy Das
sanjoy at playingwithpointers.com
Sat Feb 21 14:07:33 PST 2015
Author: sanjoy
Date: Sat Feb 21 16:07:32 2015
New Revision: 230150
URL: http://llvm.org/viewvc/llvm-project?rev=230150&view=rev
Log:
IRCE: use SCEVs instead of llvm::Value's for intermediate
calculations. Semantically non-functional change.
This gets rid of some of the SCEV -> Value -> SCEV round tripping and
the Construct(SMin|SMax)Of and MaybeSimplify helper routines.
Modified:
llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
llvm/trunk/test/Transforms/IRCE/multiple-access-no-preloop.ll
llvm/trunk/test/Transforms/IRCE/single-access-no-preloop.ll
llvm/trunk/test/Transforms/IRCE/single-access-with-preloop.ll
Modified: llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp?rev=230150&r1=230149&r2=230150&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp Sat Feb 21 16:07:32 2015
@@ -143,17 +143,17 @@ public:
/// R.getEnd() sle R.getBegin(), then R denotes the empty range.
class Range {
- Value *Begin;
- Value *End;
+ const SCEV *Begin;
+ const SCEV *End;
public:
- Range(Value *Begin, Value *End) : Begin(Begin), End(End) {
+ Range(const SCEV *Begin, const SCEV *End) : Begin(Begin), End(End) {
assert(Begin->getType() == End->getType() && "ill-typed range!");
}
Type *getType() const { return Begin->getType(); }
- Value *getBegin() const { return Begin; }
- Value *getEnd() const { return End; }
+ const SCEV *getBegin() const { return Begin; }
+ const SCEV *getEnd() const { return End; }
};
typedef SpecificBumpPtrAllocator<InductiveRangeCheck> AllocatorTy;
@@ -394,21 +394,6 @@ InductiveRangeCheck::create(InductiveRan
return IRC;
}
-static Value *MaybeSimplify(Value *V) {
- if (Instruction *I = dyn_cast<Instruction>(V))
- if (Value *Simplified = SimplifyInstruction(I))
- return Simplified;
- return V;
-}
-
-static Value *ConstructSMinOf(Value *X, Value *Y, IRBuilder<> &B) {
- return MaybeSimplify(B.CreateSelect(B.CreateICmpSLT(X, Y), X, Y));
-}
-
-static Value *ConstructSMaxOf(Value *X, Value *Y, IRBuilder<> &B) {
- return MaybeSimplify(B.CreateSelect(B.CreateICmpSGT(X, Y), X, Y));
-}
-
namespace {
/// This class is used to constrain loops to run within a given iteration space.
@@ -738,35 +723,36 @@ LoopConstrainer::calculateSubRanges(Valu
SCEVExpander Expander(SE, "irce");
Instruction *InsertPt = OriginalPreheader->getTerminator();
- Value *LatchCountV =
- MaybeSimplify(Expander.expandCodeFor(LatchTakenCount, Ty, InsertPt));
-
- IRBuilder<> B(InsertPt);
-
LoopConstrainer::SubRanges Result;
// I think we can be more aggressive here and make this nuw / nsw if the
// addition that feeds into the icmp for the latch's terminating branch is nuw
// / nsw. In any case, a wrapping 2's complement addition is safe.
ConstantInt *One = ConstantInt::get(Ty, 1);
- HeaderCountOut = MaybeSimplify(B.CreateAdd(LatchCountV, One, "header.count"));
+ const SCEV *HeaderCountSCEV = SE.getAddExpr(LatchTakenCount, SE.getSCEV(One));
+ HeaderCountOut = Expander.expandCodeFor(HeaderCountSCEV, Ty, InsertPt);
- const SCEV *RangeBegin = SE.getSCEV(Range.getBegin());
- const SCEV *RangeEnd = SE.getSCEV(Range.getEnd());
- const SCEV *HeaderCountSCEV = SE.getSCEV(HeaderCountOut);
const SCEV *Zero = SE.getConstant(Ty, 0);
// In some cases we can prove that we don't need a pre or post loop
bool ProvablyNoPreloop =
- SE.isKnownPredicate(ICmpInst::ICMP_SLE, RangeBegin, Zero);
- if (!ProvablyNoPreloop)
- Result.ExitPreLoopAt = ConstructSMinOf(HeaderCountOut, Range.getBegin(), B);
+ SE.isKnownPredicate(ICmpInst::ICMP_SLE, Range.getBegin(), Zero);
+ if (!ProvablyNoPreloop) {
+ const SCEV *ExitPreLoopAtSCEV =
+ SE.getSMinExpr(HeaderCountSCEV, Range.getBegin());
+ Result.ExitPreLoopAt =
+ Expander.expandCodeFor(ExitPreLoopAtSCEV, Ty, InsertPt);
+ }
bool ProvablyNoPostLoop =
- SE.isKnownPredicate(ICmpInst::ICMP_SLE, HeaderCountSCEV, RangeEnd);
- if (!ProvablyNoPostLoop)
- Result.ExitMainLoopAt = ConstructSMinOf(HeaderCountOut, Range.getEnd(), B);
+ SE.isKnownPredicate(ICmpInst::ICMP_SLE, HeaderCountSCEV, Range.getEnd());
+ if (!ProvablyNoPostLoop) {
+ const SCEV *ExitMainLoopAtSCEV =
+ SE.getSMinExpr(HeaderCountSCEV, Range.getEnd());
+ Result.ExitMainLoopAt =
+ Expander.expandCodeFor(ExitMainLoopAtSCEV, Ty, InsertPt);
+ }
return Result;
}
@@ -1131,18 +1117,15 @@ InductiveRangeCheck::computeSafeIteratio
return None;
}
- Value *OffsetV = SCEVExpander(SE, "safe.itr.space").expandCodeFor(
- getOffset(), getOffset()->getType(), B.GetInsertPoint());
- OffsetV = MaybeSimplify(OffsetV);
-
- Value *Begin = MaybeSimplify(B.CreateNeg(OffsetV));
- Value *End = MaybeSimplify(B.CreateSub(getLength(), OffsetV));
+ const SCEV *Begin = SE.getNegativeSCEV(getOffset());
+ const SCEV *End = SE.getMinusSCEV(SE.getSCEV(getLength()), getOffset());
return InductiveRangeCheck::Range(Begin, End);
}
static Optional<InductiveRangeCheck::Range>
-IntersectRange(const Optional<InductiveRangeCheck::Range> &R1,
+IntersectRange(ScalarEvolution &SE,
+ const Optional<InductiveRangeCheck::Range> &R1,
const InductiveRangeCheck::Range &R2, IRBuilder<> &B) {
if (!R1.hasValue())
return R2;
@@ -1153,9 +1136,10 @@ IntersectRange(const Optional<InductiveR
if (R1Value.getType() != R2.getType())
return None;
- Value *NewMin = ConstructSMaxOf(R1Value.getBegin(), R2.getBegin(), B);
- Value *NewMax = ConstructSMinOf(R1Value.getEnd(), R2.getEnd(), B);
- return InductiveRangeCheck::Range(NewMin, NewMax);
+ const SCEV *NewBegin = SE.getSMaxExpr(R1Value.getBegin(), R2.getBegin());
+ const SCEV *NewEnd = SE.getSMinExpr(R1Value.getEnd(), R2.getEnd());
+
+ return InductiveRangeCheck::Range(NewBegin, NewEnd);
}
bool InductiveRangeCheckElimination::runOnLoop(Loop *L, LPPassManager &LPM) {
@@ -1202,7 +1186,7 @@ bool InductiveRangeCheckElimination::run
auto Result = IRC->computeSafeIterationSpace(SE, B);
if (Result.hasValue()) {
auto MaybeSafeIterRange =
- IntersectRange(SafeIterRange, Result.getValue(), B);
+ IntersectRange(SE, SafeIterRange, Result.getValue(), B);
if (MaybeSafeIterRange.hasValue()) {
RangeChecksToEliminate.push_back(IRC);
SafeIterRange = MaybeSafeIterRange.getValue();
Modified: llvm/trunk/test/Transforms/IRCE/multiple-access-no-preloop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IRCE/multiple-access-no-preloop.ll?rev=230150&r1=230149&r2=230150&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IRCE/multiple-access-no-preloop.ll (original)
+++ llvm/trunk/test/Transforms/IRCE/multiple-access-no-preloop.ll Sat Feb 21 16:07:32 2015
@@ -37,10 +37,14 @@ define void @multiple_access_no_preloop(
; CHECK-LABEL: multiple_access_no_preloop
; CHECK-LABEL: loop.preheader:
-; CHECK: [[smaller_len_cmp:[^ ]+]] = icmp slt i32 %len.a, %len.b
-; CHECK: [[smaller_len:[^ ]+]] = select i1 [[smaller_len_cmp]], i32 %len.a, i32 %len.b
-; CHECK: [[upper_bound_cmp:[^ ]+]] = icmp slt i32 %n, %3
-; CHECK: [[upper_bound:[^ ]+]] = select i1 %5, i32 %n, i32 %3
+; CHECK: [[not_len_b:[^ ]+]] = sub i32 -1, %len.b
+; CHECK: [[not_len_a:[^ ]+]] = sub i32 -1, %len.a
+; CHECK: [[smax_not_len_cond:[^ ]+]] = icmp sgt i32 [[not_len_b]], [[not_len_a]]
+; CHECK: [[smax_not_len:[^ ]+]] = select i1 [[smax_not_len_cond]], i32 [[not_len_b]], i32 [[not_len_a]]
+; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
+; CHECK: [[not_upper_limit_cond:[^ ]+]] = icmp sgt i32 [[smax_not_len]], [[not_n]]
+; CHECK: [[not_upper_limit:[^ ]+]] = select i1 [[not_upper_limit_cond]], i32 [[smax_not_len]], i32 [[not_n]]
+; CHECK: [[upper_limit:[^ ]+]] = sub i32 -1, [[not_upper_limit]]
; CHECK-LABEL: loop:
; CHECK: br i1 true, label %in.bounds.a, label %out.of.bounds
@@ -49,7 +53,7 @@ define void @multiple_access_no_preloop(
; CHECK: br i1 true, label %in.bounds.b, label %out.of.bounds
; CHECK-LABEL: in.bounds.b:
-; CHECK: [[main_loop_cond:[^ ]+]] = icmp slt i32 %idx.next, [[upper_bound]]
+; CHECK: [[main_loop_cond:[^ ]+]] = icmp slt i32 %idx.next, [[upper_limit]]
; CHECK: br i1 [[main_loop_cond]], label %loop, label %main.exit.selector
; CHECK-LABEL: in.bounds.b.postloop:
Modified: llvm/trunk/test/Transforms/IRCE/single-access-no-preloop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IRCE/single-access-no-preloop.ll?rev=230150&r1=230149&r2=230150&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IRCE/single-access-no-preloop.ll (original)
+++ llvm/trunk/test/Transforms/IRCE/single-access-no-preloop.ll Sat Feb 21 16:07:32 2015
@@ -83,9 +83,11 @@ define void @single_access_no_preloop_wi
; CHECK-LABEL: single_access_no_preloop_with_offset
; CHECK-LABEL: loop.preheader:
-; CHECK: [[safe_range_end:[^ ]+]] = sub i32 %len, 4
-; CHECK: [[exit_main_loop_at_cmp:[^ ]+]] = icmp slt i32 %n, [[safe_range_end]]
-; CHECK: [[exit_main_loop_at:[^ ]+]] = select i1 [[exit_main_loop_at_cmp]], i32 %n, i32 [[safe_range_end]]
+; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
+; CHECK: [[not_safe_range_end:[^ ]+]] = sub i32 3, %len
+; CHECK: [[not_exit_main_loop_at_cmp:[^ ]+]] = icmp sgt i32 [[not_n]], [[not_safe_range_end]]
+; CHECK: [[not_exit_main_loop_at:[^ ]+]] = select i1 [[not_exit_main_loop_at_cmp]], i32 [[not_n]], i32 [[not_safe_range_end]]
+; CHECK: [[exit_main_loop_at:[^ ]+]] = sub i32 -1, [[not_exit_main_loop_at]]
; CHECK: [[enter_main_loop:[^ ]+]] = icmp slt i32 0, [[exit_main_loop_at]]
; CHECK: br i1 [[enter_main_loop]], label %loop, label %main.pseudo.exit
Modified: llvm/trunk/test/Transforms/IRCE/single-access-with-preloop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IRCE/single-access-with-preloop.ll?rev=230150&r1=230149&r2=230150&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IRCE/single-access-with-preloop.ll (original)
+++ llvm/trunk/test/Transforms/IRCE/single-access-with-preloop.ll Sat Feb 21 16:07:32 2015
@@ -29,12 +29,16 @@ define void @single_access_with_preloop(
}
; CHECK-LABEL: loop.preheader:
-; CHECK: [[safe_start:[^ ]+]] = sub i32 0, %offset
-; CHECK: [[safe_end:[^ ]+]] = sub i32 %len, %offset
-; CHECK: [[exit_preloop_at_cond:[^ ]+]] = icmp slt i32 %n, [[safe_start]]
-; CHECK: [[exit_preloop_at:[^ ]+]] = select i1 [[exit_preloop_at_cond]], i32 %n, i32 [[safe_start]]
-; CHECK: [[exit_mainloop_at_cond:[^ ]+]] = icmp slt i32 %n, [[safe_end]]
-; CHECK: [[exit_mainloop_at:[^ ]+]] = select i1 [[exit_mainloop_at_cond]], i32 %n, i32 [[safe_end]]
+; CHECK: [[not_safe_start:[^ ]+]] = add i32 %offset, -1
+; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
+; CHECK: [[not_exit_preloop_at_cond:[^ ]+]] = icmp sgt i32 [[not_safe_start]], [[not_n]]
+; CHECK: [[not_exit_preloop_at:[^ ]+]] = select i1 [[not_exit_preloop_at_cond]], i32 [[not_safe_start]], i32 [[not_n]]
+; CHECK: [[exit_preloop_at:[^ ]+]] = sub i32 -1, [[not_exit_preloop_at]]
+
+; CHECK: [[not_safe_end:[^ ]+]] = sub i32 [[not_safe_start]], %len
+; CHECK: [[not_exit_mainloop_at_cond:[^ ]+]] = icmp sgt i32 [[not_safe_end]], [[not_n]]
+; CHECK: [[not_exit_mainloop_at:[^ ]+]] = select i1 [[not_exit_mainloop_at_cond]], i32 [[not_safe_end]], i32 [[not_n]]
+; CHECK: [[exit_mainloop_at:[^ ]+]] = sub i32 -1, [[not_exit_mainloop_at]]
; CHECK-LABEL: in.bounds:
; CHECK: [[continue_mainloop_cond:[^ ]+]] = icmp slt i32 %idx.next, [[exit_mainloop_at]]
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