Changes in directory llvm/lib/Target/SparcV8:
SparcV8ISelDAGToDAG.cpp updated: 1.64 -> 1.65
---
Log message:
When lowering SELECT_CC, see if the input is a lowered SETCC. If so, fold
the two operations together. This allows us to compile this:
void %two(int %a, int* %b) {
%tmp.2 = seteq int %a, 0
%tmp.0.0 = select bool %tmp.2, int 10, int 20
store int %tmp.0.0, int* %b
ret void
}
into:
two:
save -96, %o6, %o6
or %g0, 20, %l0
or %g0, 10, %l1
subcc %i0, 0, %l2
be .LBBtwo_2 ! entry
nop
.LBBtwo_1: ! entry
or %g0, %l0, %l1
.LBBtwo_2: ! entry
st %l1, [%i1]
restore %g0, %g0, %g0
retl
nop
instead of:
two:
save -96, %o6, %o6
sethi 0, %l0
or %g0, 1, %l1
or %g0, 20, %l2
or %g0, 10, %l3
subcc %i0, 0, %l4
be .LBBtwo_2 ! entry
nop
.LBBtwo_1: ! entry
or %g0, %l0, %l1
.LBBtwo_2: ! entry
subcc %l1, 0, %l0
bne .LBBtwo_4 ! entry
nop
.LBBtwo_3: ! entry
or %g0, %l2, %l3
.LBBtwo_4: ! entry
st %l3, [%i1]
restore %g0, %g0, %g0
retl
nop
---
Diffs of the changes: (+18 -0)
SparcV8ISelDAGToDAG.cpp | 18 ++++++++++++++++++
1 files changed, 18 insertions(+)
Index: llvm/lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp
diff -u llvm/lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp:1.64
llvm/lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp:1.65
--- llvm/lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp:1.64 Sun Jan 29
22:09:04 2006
+++ llvm/lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp Sun Jan 29 22:34:44 2006
@@ -669,6 +669,24 @@
SDOperand TrueVal = Op.getOperand(2);
SDOperand FalseVal = Op.getOperand(3);
+ // If this is a select_cc of a "setcc", and if the setcc got lowered into
+ // an CMP[IF]CC/SELECT_[IF]CC pair, find the original compared values.
+ if (isa<ConstantSDNode>(RHS) && cast<ConstantSDNode>(RHS)->getValue() ==
0&&
+ CC == ISD::SETNE &&
+ ((LHS.getOpcode() == V8ISD::SELECT_ICC &&
+ LHS.getOperand(3).getOpcode() == V8ISD::CMPICC) ||
+ (LHS.getOpcode() == V8ISD::SELECT_FCC &&
+ LHS.getOperand(3).getOpcode() == V8ISD::CMPFCC)) &&
+ isa<ConstantSDNode>(LHS.getOperand(0)) &&
+ isa<ConstantSDNode>(LHS.getOperand(1)) &&
+ cast<ConstantSDNode>(LHS.getOperand(0))->getValue() == 1 &&
+ cast<ConstantSDNode>(LHS.getOperand(1))->getValue() == 0) {
+ SDOperand CMPCC = LHS.getOperand(3);
+ CC = cast<ConstantSDNode>(LHS.getOperand(2))->getValue();
+ LHS = CMPCC.getOperand(0);
+ RHS = CMPCC.getOperand(1);
+ }
+
SDOperand CompareFlag;
unsigned Opc;
if (LHS.getValueType() == MVT::i32) {
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