forked from OSchip/llvm-project
Generalize the cast-of-addrec folding to handle folding of SCEVs like
(sext i8 {-128,+,1} to i64) to i64 {-128,+,1}, where the iteration
crosses from negative to positive, but is still safe if the trip
count is within range.
llvm-svn: 70421
This commit is contained in:
Dan Gohman
parent
d6bef2edab
commit
494dac3f84
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@ -718,7 +718,7 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op,
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SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop());
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if (!isa<SCEVCouldNotCompute>(BECount)) {
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// Manually compute the final value for AR, checking for
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// overflow at each step.
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// overflow.
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SCEVHandle Start = AR->getStart();
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SCEVHandle Step = AR->getStepRecurrence(*this);
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@ -730,41 +730,34 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op,
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getTruncateOrZeroExtend(CastedBECount, BECount->getType())) {
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const Type *WideTy =
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IntegerType::get(getTypeSizeInBits(Start->getType()) * 2);
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// Check whether Start+Step*BECount has no unsigned overflow.
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SCEVHandle ZMul =
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getMulExpr(CastedBECount,
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getTruncateOrZeroExtend(Step, Start->getType()));
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// Check whether Start+Step*BECount has no unsigned overflow.
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if (getZeroExtendExpr(ZMul, WideTy) ==
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getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
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getZeroExtendExpr(Step, WideTy))) {
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SCEVHandle Add = getAddExpr(Start, ZMul);
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if (getZeroExtendExpr(Add, WideTy) ==
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getAddExpr(getZeroExtendExpr(Start, WideTy),
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getZeroExtendExpr(ZMul, WideTy)))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getZeroExtendExpr(Start, Ty),
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getZeroExtendExpr(Step, Ty),
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AR->getLoop());
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}
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SCEVHandle Add = getAddExpr(Start, ZMul);
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if (getZeroExtendExpr(Add, WideTy) ==
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getAddExpr(getZeroExtendExpr(Start, WideTy),
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getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
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getZeroExtendExpr(Step, WideTy))))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getZeroExtendExpr(Start, Ty),
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getZeroExtendExpr(Step, Ty),
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AR->getLoop());
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// Similar to above, only this time treat the step value as signed.
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// This covers loops that count down.
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SCEVHandle SMul =
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getMulExpr(CastedBECount,
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getTruncateOrSignExtend(Step, Start->getType()));
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// Check whether Start+Step*BECount has no unsigned overflow.
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if (getSignExtendExpr(SMul, WideTy) ==
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getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
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getSignExtendExpr(Step, WideTy))) {
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SCEVHandle Add = getAddExpr(Start, SMul);
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if (getZeroExtendExpr(Add, WideTy) ==
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getAddExpr(getZeroExtendExpr(Start, WideTy),
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getSignExtendExpr(SMul, WideTy)))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getZeroExtendExpr(Start, Ty),
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getSignExtendExpr(Step, Ty),
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AR->getLoop());
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}
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Add = getAddExpr(Start, SMul);
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if (getZeroExtendExpr(Add, WideTy) ==
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getAddExpr(getZeroExtendExpr(Start, WideTy),
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getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
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getSignExtendExpr(Step, WideTy))))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getZeroExtendExpr(Start, Ty),
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getSignExtendExpr(Step, Ty),
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AR->getLoop());
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}
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}
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}
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@ -807,37 +800,31 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op,
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SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop());
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if (!isa<SCEVCouldNotCompute>(BECount)) {
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// Manually compute the final value for AR, checking for
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// overflow at each step.
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// overflow.
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SCEVHandle Start = AR->getStart();
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SCEVHandle Step = AR->getStepRecurrence(*this);
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// Check whether the backedge-taken count can be losslessly casted to
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// the addrec's type. The count needs to be the same whether sign
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// extended or zero extended.
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// the addrec's type. The count is always unsigned.
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SCEVHandle CastedBECount =
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getTruncateOrZeroExtend(BECount, Start->getType());
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if (BECount ==
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getTruncateOrZeroExtend(CastedBECount, BECount->getType()) &&
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BECount ==
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getTruncateOrSignExtend(CastedBECount, BECount->getType())) {
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getTruncateOrZeroExtend(CastedBECount, BECount->getType())) {
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const Type *WideTy =
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IntegerType::get(getTypeSizeInBits(Start->getType()) * 2);
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// Check whether Start+Step*BECount has no signed overflow.
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SCEVHandle SMul =
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getMulExpr(CastedBECount,
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getTruncateOrSignExtend(Step, Start->getType()));
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// Check whether Start+Step*BECount has no signed overflow.
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if (getSignExtendExpr(SMul, WideTy) ==
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getMulExpr(getSignExtendExpr(CastedBECount, WideTy),
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getSignExtendExpr(Step, WideTy))) {
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SCEVHandle Add = getAddExpr(Start, SMul);
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if (getSignExtendExpr(Add, WideTy) ==
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getAddExpr(getSignExtendExpr(Start, WideTy),
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getSignExtendExpr(SMul, WideTy)))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getSignExtendExpr(Start, Ty),
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getSignExtendExpr(Step, Ty),
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AR->getLoop());
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}
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SCEVHandle Add = getAddExpr(Start, SMul);
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if (getSignExtendExpr(Add, WideTy) ==
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getAddExpr(getSignExtendExpr(Start, WideTy),
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getMulExpr(getZeroExtendExpr(CastedBECount, WideTy),
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getSignExtendExpr(Step, WideTy))))
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// Return the expression with the addrec on the outside.
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return getAddRecExpr(getSignExtendExpr(Start, Ty),
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getSignExtendExpr(Step, Ty),
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AR->getLoop());
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}
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}
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}
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@ -0,0 +1,31 @@
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; RUN: llvm-as < %s | opt -disable-output -scalar-evolution -analyze \
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; RUN: | grep { --> \{-128,+,1\}<bb1> Exits: 127} | count 5
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; Convert (sext {-128,+,1}) to {sext(-128),+,sext(1)}, since the
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; trip count is within range where this is safe.
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
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target triple = "x86_64-unknown-linux-gnu"
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define void @foo(double* nocapture %x) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%i.0.reg2mem.0 = phi i64 [ -128, %bb1.thread ], [ %8, %bb1 ] ; <i64> [#uses=3]
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%0 = trunc i64 %i.0.reg2mem.0 to i8 ; <i8> [#uses=1]
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%1 = trunc i64 %i.0.reg2mem.0 to i9 ; <i8> [#uses=1]
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%2 = sext i9 %1 to i64 ; <i64> [#uses=1]
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%3 = getelementptr double* %x, i64 %2 ; <double*> [#uses=1]
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%4 = load double* %3, align 8 ; <double> [#uses=1]
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%5 = mul double %4, 3.900000e+00 ; <double> [#uses=1]
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%6 = sext i8 %0 to i64 ; <i64> [#uses=1]
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%7 = getelementptr double* %x, i64 %6 ; <double*> [#uses=1]
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store double %5, double* %7, align 8
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%8 = add i64 %i.0.reg2mem.0, 1 ; <i64> [#uses=2]
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%9 = icmp sgt i64 %8, 127 ; <i1> [#uses=1]
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br i1 %9, label %return, label %bb1
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return: ; preds = %bb1
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ret void
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}
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@ -0,0 +1,100 @@
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; RUN: llvm-as < %s | opt -disable-output -scalar-evolution -analyze \
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; RUN: | grep { --> (sext i. \{.\*,+,.\*\}<bb1> to i64)} | count 5
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; Don't convert (sext {...,+,...}) to {sext(...),+,sext(...)} in cases
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; where the trip count is not within range.
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
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target triple = "x86_64-unknown-linux-gnu"
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define void @foo0(double* nocapture %x) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%i.0.reg2mem.0 = phi i64 [ -128, %bb1.thread ], [ %8, %bb1 ] ; <i64> [#uses=3]
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%0 = trunc i64 %i.0.reg2mem.0 to i7 ; <i8> [#uses=1]
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%1 = trunc i64 %i.0.reg2mem.0 to i9 ; <i8> [#uses=1]
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%2 = sext i9 %1 to i64 ; <i64> [#uses=1]
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%3 = getelementptr double* %x, i64 %2 ; <double*> [#uses=1]
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%4 = load double* %3, align 8 ; <double> [#uses=1]
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%5 = mul double %4, 3.900000e+00 ; <double> [#uses=1]
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%6 = sext i7 %0 to i64 ; <i64> [#uses=1]
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%7 = getelementptr double* %x, i64 %6 ; <double*> [#uses=1]
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store double %5, double* %7, align 8
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%8 = add i64 %i.0.reg2mem.0, 1 ; <i64> [#uses=2]
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%9 = icmp sgt i64 %8, 127 ; <i1> [#uses=1]
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br i1 %9, label %return, label %bb1
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return: ; preds = %bb1
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ret void
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}
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define void @foo1(double* nocapture %x) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%i.0.reg2mem.0 = phi i64 [ -128, %bb1.thread ], [ %8, %bb1 ] ; <i64> [#uses=3]
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%0 = trunc i64 %i.0.reg2mem.0 to i8 ; <i8> [#uses=1]
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%1 = trunc i64 %i.0.reg2mem.0 to i9 ; <i8> [#uses=1]
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%2 = sext i9 %1 to i64 ; <i64> [#uses=1]
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%3 = getelementptr double* %x, i64 %2 ; <double*> [#uses=1]
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%4 = load double* %3, align 8 ; <double> [#uses=1]
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%5 = mul double %4, 3.900000e+00 ; <double> [#uses=1]
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%6 = sext i8 %0 to i64 ; <i64> [#uses=1]
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%7 = getelementptr double* %x, i64 %6 ; <double*> [#uses=1]
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store double %5, double* %7, align 8
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%8 = add i64 %i.0.reg2mem.0, 1 ; <i64> [#uses=2]
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%9 = icmp sgt i64 %8, 128 ; <i1> [#uses=1]
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br i1 %9, label %return, label %bb1
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return: ; preds = %bb1
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ret void
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}
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define void @foo2(double* nocapture %x) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%i.0.reg2mem.0 = phi i64 [ -129, %bb1.thread ], [ %8, %bb1 ] ; <i64> [#uses=3]
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%0 = trunc i64 %i.0.reg2mem.0 to i8 ; <i8> [#uses=1]
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%1 = trunc i64 %i.0.reg2mem.0 to i9 ; <i8> [#uses=1]
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%2 = sext i9 %1 to i64 ; <i64> [#uses=1]
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%3 = getelementptr double* %x, i64 %2 ; <double*> [#uses=1]
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%4 = load double* %3, align 8 ; <double> [#uses=1]
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%5 = mul double %4, 3.900000e+00 ; <double> [#uses=1]
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%6 = sext i8 %0 to i64 ; <i64> [#uses=1]
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%7 = getelementptr double* %x, i64 %6 ; <double*> [#uses=1]
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store double %5, double* %7, align 8
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%8 = add i64 %i.0.reg2mem.0, 1 ; <i64> [#uses=2]
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%9 = icmp sgt i64 %8, 127 ; <i1> [#uses=1]
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br i1 %9, label %return, label %bb1
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return: ; preds = %bb1
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ret void
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}
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define void @foo3(double* nocapture %x) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%i.0.reg2mem.0 = phi i64 [ -128, %bb1.thread ], [ %8, %bb1 ] ; <i64> [#uses=3]
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%0 = trunc i64 %i.0.reg2mem.0 to i8 ; <i8> [#uses=1]
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%1 = trunc i64 %i.0.reg2mem.0 to i9 ; <i8> [#uses=1]
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%2 = sext i9 %1 to i64 ; <i64> [#uses=1]
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%3 = getelementptr double* %x, i64 %2 ; <double*> [#uses=1]
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%4 = load double* %3, align 8 ; <double> [#uses=1]
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%5 = mul double %4, 3.900000e+00 ; <double> [#uses=1]
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%6 = sext i8 %0 to i64 ; <i64> [#uses=1]
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%7 = getelementptr double* %x, i64 %6 ; <double*> [#uses=1]
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store double %5, double* %7, align 8
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%8 = add i64 %i.0.reg2mem.0, -1 ; <i64> [#uses=2]
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%9 = icmp sgt i64 %8, 127 ; <i1> [#uses=1]
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br i1 %9, label %return, label %bb1
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return: ; preds = %bb1
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ret void
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}
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