[llvm-commits] [llvm] r94339 - in /llvm/trunk: include/llvm/Support/PatternMatch.h lib/Target/PowerPC/README.txt lib/Transforms/InstCombine/InstCombineAndOrXor.cpp lib/Transforms/InstCombine/InstCombineCasts.cpp lib/Transforms/InstCombine/InstCombineSelect.cpp test/Transforms/InstCombine/logical-select.ll
Chris Lattner
sabre at nondot.org
Sat Jan 23 16:09:49 PST 2010
Author: lattner
Date: Sat Jan 23 18:09:49 2010
New Revision: 94339
URL: http://llvm.org/viewvc/llvm-project?rev=94339&view=rev
Log:
change the canonical form of "cond ? -1 : 0" to be
"sext cond" instead of a select. This simplifies some instcombine
code, matches the policy for zext (cond ? 1 : 0 -> zext), and allows
us to generate better code for a testcase on ppc.
Modified:
llvm/trunk/include/llvm/Support/PatternMatch.h
llvm/trunk/lib/Target/PowerPC/README.txt
llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/trunk/test/Transforms/InstCombine/logical-select.ll
Modified: llvm/trunk/include/llvm/Support/PatternMatch.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/PatternMatch.h?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/PatternMatch.h (original)
+++ llvm/trunk/include/llvm/Support/PatternMatch.h Sat Jan 23 18:09:49 2010
@@ -423,7 +423,7 @@
}
/// m_SelectCst - This matches a select of two constants, e.g.:
-/// m_SelectCst(m_Value(V), -1, 0)
+/// m_SelectCst<-1, 0>(m_Value(V))
template<int64_t L, int64_t R, typename Cond>
inline SelectClass_match<Cond, constantint_ty<L>, constantint_ty<R> >
m_SelectCst(const Cond &C) {
@@ -466,6 +466,20 @@
m_Trunc(const OpTy &Op) {
return CastClass_match<OpTy, Instruction::Trunc>(Op);
}
+
+/// m_SExt
+template<typename OpTy>
+inline CastClass_match<OpTy, Instruction::SExt>
+m_SExt(const OpTy &Op) {
+ return CastClass_match<OpTy, Instruction::SExt>(Op);
+}
+
+/// m_ZExt
+template<typename OpTy>
+inline CastClass_match<OpTy, Instruction::ZExt>
+m_ZExt(const OpTy &Op) {
+ return CastClass_match<OpTy, Instruction::ZExt>(Op);
+}
//===----------------------------------------------------------------------===//
Modified: llvm/trunk/lib/Target/PowerPC/README.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/README.txt?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/README.txt (original)
+++ llvm/trunk/lib/Target/PowerPC/README.txt Sat Jan 23 18:09:49 2010
@@ -640,22 +640,19 @@
define i32 @bar(i32 %x) nounwind readnone ssp {
entry:
%0 = icmp eq i32 %x, 0 ; <i1> [#uses=1]
- %neg = select i1 %0, i32 -1, i32 0 ; <i32> [#uses=1]
+ %neg = sext i1 %0 to i32 ; <i32> [#uses=1]
ret i32 %neg
}
to:
_bar:
- cmplwi cr0, r3, 0
- li r3, -1
- beq cr0, LBB1_2
-; BB#1: ; %entry
- li r3, 0
-LBB1_2: ; %entry
+ cntlzw r2, r3
+ slwi r2, r2, 26
+ srawi r3, r2, 31
blr
-it would be much better to produce:
+it would be better to produce:
_bar:
addic r3,r3,-1
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Sat Jan 23 18:09:49 2010
@@ -1142,19 +1142,15 @@
Value *C, Value *D) {
// If A is not a select of -1/0, this cannot match.
Value *Cond = 0;
- if (!match(A, m_SelectCst<-1, 0>(m_Value(Cond))))
+ if (!match(A, m_SExt(m_Value(Cond))))
return 0;
// ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
- if (match(D, m_SelectCst<0, -1>(m_Specific(Cond))))
- return SelectInst::Create(Cond, C, B);
- if (match(D, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
+ if (match(D, m_Not(m_SExt(m_Specific(Cond)))))
return SelectInst::Create(Cond, C, B);
// ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
if (match(B, m_SelectCst<0, -1>(m_Specific(Cond))))
return SelectInst::Create(Cond, C, D);
- if (match(B, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
- return SelectInst::Create(Cond, C, D);
return 0;
}
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp Sat Jan 23 18:09:49 2010
@@ -923,12 +923,6 @@
Value *Src = CI.getOperand(0);
const Type *SrcTy = Src->getType(), *DestTy = CI.getType();
- // Canonicalize sign-extend from i1 to a select.
- if (Src->getType()->isInteger(1))
- return SelectInst::Create(Src,
- Constant::getAllOnesValue(CI.getType()),
- Constant::getNullValue(CI.getType()));
-
// Attempt to extend the entire input expression tree to the destination
// type. Only do this if the dest type is a simple type, don't convert the
// expression tree to something weird like i93 unless the source is also
@@ -968,6 +962,30 @@
return BinaryOperator::CreateAShr(Res, ShAmt);
}
+
+ // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if signed
+ // (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed
+ {
+ ICmpInst::Predicate Pred; Value *CmpLHS; ConstantInt *CmpRHS;
+ if (match(Src, m_ICmp(Pred, m_Value(CmpLHS), m_ConstantInt(CmpRHS)))) {
+ // sext (x <s 0) to i32 --> x>>s31 true if signbit set.
+ // sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear.
+ if ((Pred == ICmpInst::ICMP_SLT && CmpRHS->isZero()) ||
+ (Pred == ICmpInst::ICMP_SGT && CmpRHS->isAllOnesValue())) {
+ Value *Sh = ConstantInt::get(CmpLHS->getType(),
+ CmpLHS->getType()->getScalarSizeInBits()-1);
+ Value *In = Builder->CreateAShr(CmpLHS, Sh, CmpLHS->getName()+".lobit");
+ if (In->getType() != CI.getType())
+ In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/, "tmp");
+
+ if (Pred == ICmpInst::ICMP_SGT)
+ In = Builder->CreateNot(In, In->getName()+".not");
+ return ReplaceInstUsesWith(CI, In);
+ }
+ }
+ }
+
+
// If the input is a shl/ashr pair of a same constant, then this is a sign
// extension from a smaller value. If we could trust arbitrary bitwidth
// integers, we could turn this into a truncate to the smaller bit and then
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Sat Jan 23 18:09:49 2010
@@ -326,44 +326,6 @@
break;
}
}
-
- // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if signed
- // (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed
- CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
- if (match(TrueVal, m_ConstantInt<-1>()) &&
- match(FalseVal, m_ConstantInt<0>()))
- Pred = ICI->getPredicate();
- else if (match(TrueVal, m_ConstantInt<0>()) &&
- match(FalseVal, m_ConstantInt<-1>()))
- Pred = CmpInst::getInversePredicate(ICI->getPredicate());
-
- if (Pred != CmpInst::BAD_ICMP_PREDICATE) {
- // If we are just checking for a icmp eq of a single bit and zext'ing it
- // to an integer, then shift the bit to the appropriate place and then
- // cast to integer to avoid the comparison.
- const APInt &Op1CV = CI->getValue();
-
- // sext (x <s 0) to i32 --> x>>s31 true if signbit set.
- // sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear.
- if ((Pred == ICmpInst::ICMP_SLT && Op1CV == 0) ||
- (Pred == ICmpInst::ICMP_SGT && Op1CV.isAllOnesValue())) {
- Value *In = ICI->getOperand(0);
- Value *Sh = ConstantInt::get(In->getType(),
- In->getType()->getScalarSizeInBits()-1);
- In = InsertNewInstBefore(BinaryOperator::CreateAShr(In, Sh,
- In->getName()+".lobit"),
- *ICI);
- if (In->getType() != SI.getType())
- In = CastInst::CreateIntegerCast(In, SI.getType(),
- true/*SExt*/, "tmp", ICI);
-
- if (Pred == ICmpInst::ICMP_SGT)
- In = InsertNewInstBefore(BinaryOperator::CreateNot(In,
- In->getName()+".not"), *ICI);
-
- return ReplaceInstUsesWith(SI, In);
- }
- }
}
if (CmpLHS == TrueVal && CmpRHS == FalseVal) {
@@ -516,16 +478,25 @@
if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) {
// select C, 1, 0 -> zext C to int
- if (FalseValC->isZero() && TrueValC->getValue() == 1) {
- return CastInst::Create(Instruction::ZExt, CondVal, SI.getType());
- } else if (TrueValC->isZero() && FalseValC->getValue() == 1) {
- // select C, 0, 1 -> zext !C to int
- Value *NotCond =
- InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
- "not."+CondVal->getName()), SI);
- return CastInst::Create(Instruction::ZExt, NotCond, SI.getType());
+ if (FalseValC->isZero() && TrueValC->getValue() == 1)
+ return new ZExtInst(CondVal, SI.getType());
+
+ // select C, -1, 0 -> sext C to int
+ if (FalseValC->isZero() && TrueValC->isAllOnesValue())
+ return new SExtInst(CondVal, SI.getType());
+
+ // select C, 0, 1 -> zext !C to int
+ if (TrueValC->isZero() && FalseValC->getValue() == 1) {
+ Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName());
+ return new ZExtInst(NotCond, SI.getType());
}
+ // select C, 0, -1 -> sext !C to int
+ if (TrueValC->isZero() && FalseValC->isAllOnesValue()) {
+ Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName());
+ return new SExtInst(NotCond, SI.getType());
+ }
+
if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) {
// If one of the constants is zero (we know they can't both be) and we
// have an icmp instruction with zero, and we have an 'and' with the
@@ -547,8 +518,7 @@
ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
Value *V = ICA;
if (ShouldNotVal)
- V = InsertNewInstBefore(BinaryOperator::Create(
- Instruction::Xor, V, ICA->getOperand(1)), SI);
+ V = Builder->CreateXor(V, ICA->getOperand(1));
return ReplaceInstUsesWith(SI, V);
}
}
Modified: llvm/trunk/test/Transforms/InstCombine/logical-select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/logical-select.ll?rev=94339&r1=94338&r2=94339&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/logical-select.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/logical-select.ll Sat Jan 23 18:09:49 2010
@@ -1,7 +1,4 @@
-; RUN: opt < %s -instcombine -S > %t
-; RUN: grep select %t | count 5
-; RUN: not grep and %t
-; RUN: not grep or %t
+; RUN: opt < %s -instcombine -S > FileCheck %s
define i32 @foo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
%e = icmp slt i32 %a, %b
@@ -11,6 +8,9 @@
%i = and i32 %d, %h
%j = or i32 %g, %i
ret i32 %j
+; CHECK: %e = icmp slt i32 %a, %b
+; CHECK: %j = select i1 %e, i32 %c, i32 %d
+; CHECK: ret i32 %j
}
define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
%e = icmp slt i32 %a, %b
@@ -20,6 +20,9 @@
%i = and i32 %d, %h
%j = or i32 %i, %g
ret i32 %j
+; CHECK: %e = icmp slt i32 %a, %b
+; CHECK: %j = select i1 %e, i32 %c, i32 %d
+; CHECK: ret i32 %j
}
define i32 @goo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
entry:
@@ -30,6 +33,9 @@
%2 = and i32 %not, %d
%3 = or i32 %1, %2
ret i32 %3
+; CHECK: %0 = icmp slt i32 %a, %b
+; CHECK: %1 = select i1 %0, i32 %c, i32 %d
+; CHECK: ret i32 %1
}
define i32 @poo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
entry:
@@ -40,6 +46,9 @@
%2 = and i32 %iftmp, %d
%3 = or i32 %1, %2
ret i32 %3
+; CHECK: %0 = icmp slt i32 %a, %b
+; CHECK: %1 = select i1 %0, i32 %c, i32 %d
+; CHECK: ret i32 %1
}
define i32 @par(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
@@ -51,4 +60,7 @@
%2 = and i32 %not, %d
%3 = or i32 %1, %2
ret i32 %3
+; CHECK: %0 = icmp slt i32 %a, %b
+; CHECK: %1 = select i1 %0, i32 %c, i32 %d
+; CHECK: ret i32 %1
}
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