6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-08-07 12:28:24 +00:00
Code Issues Projects Releases Wiki Activity

Avoid creating shift-by-zero SDNodes in the common case of

Browse Source 
i8* getelementptr. DAGCombine eliminates these, but this is
a fairly common case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55214 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2008-08-23 01:06:51 +00:00
parent 6f17966a80
commit 6679906d97
1 changed files with 10 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
View File

@@ -2814,16 +2814,17 @@ void SelectionDAGLowering::visitGetElementPtr(User &I) {
// If this is a multiply by a power of two, turn it into a shl // If this is a multiply by a power of two, turn it into a shl
// immediately. This is a very common case. // immediately. This is a very common case.
if (isPowerOf2_64(ElementSize)) { if (ElementSize != 1) {
unsigned Amt = Log2_64(ElementSize); if (isPowerOf2_64(ElementSize)) {
IdxN = DAG.getNode(ISD::SHL, N.getValueType(), IdxN, unsigned Amt = Log2_64(ElementSize);
DAG.getConstant(Amt, TLI.getShiftAmountTy())); IdxN = DAG.getNode(ISD::SHL, N.getValueType(), IdxN,
N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN); DAG.getConstant(Amt, TLI.getShiftAmountTy()));
continue; } else {
SDValue Scale = DAG.getIntPtrConstant(ElementSize);
IdxN = DAG.getNode(ISD::MUL, N.getValueType(), IdxN, Scale);
}
} }
SDValue Scale = DAG.getIntPtrConstant(ElementSize);
IdxN = DAG.getNode(ISD::MUL, N.getValueType(), IdxN, Scale);
N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN); N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN);
} }
} }