Changes in directory llvm/lib/Analysis:
ScalarEvolution.cpp updated: 1.68 -> 1.69
---
Log message:
teach scev to analyze X*4|1 like X*4+c. This allows us to produce:
LBB1_1: #bb
movdqa (%esi), %xmm2
movaps %xmm2, %xmm3
punpcklbw %xmm0, %xmm3
movaps %xmm3, %xmm4
punpcklwd %xmm0, %xmm4
cvtdq2ps %xmm4, %xmm4
mulps %xmm1, %xmm4
movaps %xmm4, (%edi)
leal 1(,%eax,4), %ebx
shll $4, %ebx
punpckhwd %xmm0, %xmm3
cvtdq2ps %xmm3, %xmm3
mulps %xmm1, %xmm3
movaps %xmm3, (%edx,%ebx)
leal 2(,%eax,4), %ebx
shll $4, %ebx
punpckhbw %xmm0, %xmm2
movaps %xmm2, %xmm3
punpcklwd %xmm0, %xmm3
cvtdq2ps %xmm3, %xmm3
mulps %xmm1, %xmm3
movaps %xmm3, (%edx,%ebx)
leal 3(,%eax,4), %ebx
shll $4, %ebx
punpckhwd %xmm0, %xmm2
cvtdq2ps %xmm2, %xmm2
mulps %xmm1, %xmm2
movaps %xmm2, (%edx,%ebx)
addl $64, %edi
incl %eax
addl $16, %esi
cmpl %ecx, %eax
jne LBB1_1 #bb
instead of:
LBB1_1: #bb
movdqa (%esi), %xmm2
movaps %xmm2, %xmm3
punpcklbw %xmm0, %xmm3
movaps %xmm3, %xmm4
punpcklwd %xmm0, %xmm4
cvtdq2ps %xmm4, %xmm4
mulps %xmm1, %xmm4
movaps %xmm4, (%edi)
leal 1(,%eax,4), %ebx
shll $4, %ebx
punpckhwd %xmm0, %xmm3
cvtdq2ps %xmm3, %xmm3
mulps %xmm1, %xmm3
movaps %xmm3, (%edx,%ebx)
leal 2(,%eax,4), %ebx
shll $4, %ebx
punpckhbw %xmm0, %xmm2
movaps %xmm2, %xmm3
punpcklwd %xmm0, %xmm3
cvtdq2ps %xmm3, %xmm3
mulps %xmm1, %xmm3
movaps %xmm3, (%edx,%ebx)
leal 3(,%eax,4), %ebx
shll $4, %ebx
punpckhwd %xmm0, %xmm2
cvtdq2ps %xmm2, %xmm2
mulps %xmm1, %xmm2
movaps %xmm2, (%edx,%ebx)
addl $64, %edi
incl %eax
addl $16, %esi
cmpl %ecx, %eax
jne LBB1_1 #bb
for a testcase.
---
Diffs of the changes: (+59 -1)
ScalarEvolution.cpp | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 59 insertions(+), 1 deletion(-)
Index: llvm/lib/Analysis/ScalarEvolution.cpp
diff -u llvm/lib/Analysis/ScalarEvolution.cpp:1.68
llvm/lib/Analysis/ScalarEvolution.cpp:1.69
--- llvm/lib/Analysis/ScalarEvolution.cpp:1.68 Sun Dec 10 18:12:31 2006
+++ llvm/lib/Analysis/ScalarEvolution.cpp Mon Dec 11 20:26:09 2006
@@ -1339,6 +1339,49 @@
return SCEVUnknown::get(PN);
}
+/// GetConstantFactor - Determine the largest constant factor that S has. For
+/// example, turn {4,+,8} -> 4. (S umod result) should always equal zero.
+static uint64_t GetConstantFactor(SCEVHandle S) {
+ if (SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
+ if (uint64_t V = C->getValue()->getZExtValue())
+ return V;
+ else // Zero is a multiple of everything.
+ return 1ULL << (S->getType()->getPrimitiveSizeInBits()-1);
+ }
+
+ if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
+ return GetConstantFactor(T->getOperand()) &
+ T->getType()->getIntegralTypeMask();
+ if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S))
+ return GetConstantFactor(E->getOperand());
+
+ if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
+ // The result is the min of all operands.
+ uint64_t Res = GetConstantFactor(A->getOperand(0));
+ for (unsigned i = 1, e = A->getNumOperands(); i != e && Res > 1; ++i)
+ Res = std::min(Res, GetConstantFactor(A->getOperand(i)));
+ return Res;
+ }
+
+ if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
+ // The result is the product of all the operands.
+ uint64_t Res = GetConstantFactor(M->getOperand(0));
+ for (unsigned i = 1, e = M->getNumOperands(); i != e; ++i)
+ Res *= GetConstantFactor(M->getOperand(i));
+ return Res;
+ }
+
+ if (SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
+ // FIXME: Generalize.
+ if (A->getNumOperands() == 2)
+ return std::min(GetConstantFactor(A->getOperand(0)),
+ GetConstantFactor(A->getOperand(1)));
+ // ?
+ }
+
+ // SCEVSDivExpr, SCEVUnknown.
+ return 1;
+}
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
@@ -1360,7 +1403,22 @@
case Instruction::Sub:
return SCEV::getMinusSCEV(getSCEV(I->getOperand(0)),
getSCEV(I->getOperand(1)));
-
+ case Instruction::Or:
+ // If the RHS of the Or is a constant, we may have something like:
+ // X*4+1 which got turned into X*4|1. Handle this as an add so loop
+ // optimizations will transparently handle this case.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
+ SCEVHandle LHS = getSCEV(I->getOperand(0));
+ uint64_t CommonFact = GetConstantFactor(LHS);
+ assert(CommonFact && "Common factor should at least be 1!");
+ if (CommonFact > CI->getZExtValue()) {
+ // If the LHS is a multiple that is larger than the RHS, use +.
+ return SCEVAddExpr::get(LHS,
+ getSCEV(I->getOperand(1)));
+ }
+ }
+ break;
+
case Instruction::Shl:
// Turn shift left of a constant amount into a multiply.
if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
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