constant fold FP_ROUND_INREG, ZERO_EXTEND_INREG, and SIGN_EXTEND_INREG
This allows the alpha backend to compile:
bool %test(uint %P) {
%c = seteq uint %P, 0
ret bool %c
}
into:
test:
ldgp $29, 0($27)
ZAP $16,240,$0
CMPEQ $0,0,$0
AND $0,1,$0
ret $31,($26),1
instead of:
test:
ldgp $29, 0($27)
ZAP $16,240,$0
ldiq $1,0
ZAP $1,240,$1
CMPEQ $0,$1,$0
AND $0,1,$0
ret $31,($26),1
... and fixes PR534.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20534 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index a0e5d93..fb52d11 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -946,6 +946,9 @@
"Cannot FP_ROUND_INREG integer types");
if (EVT == VT) return N1; // Not actually rounding
assert(EVT < VT && "Not rounding down!");
+
+ if (isa<ConstantFPSDNode>(N1))
+ return getNode(ISD::FP_EXTEND, VT, getNode(ISD::FP_ROUND, EVT, N1));
break;
case ISD::ZERO_EXTEND_INREG:
case ISD::SIGN_EXTEND_INREG:
@@ -955,6 +958,15 @@
if (EVT == VT) return N1; // Not actually extending
assert(EVT < VT && "Not extending!");
+ // Extending a constant? Just return the constant.
+ if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
+ SDOperand Tmp = getNode(ISD::TRUNCATE, EVT, N1);
+ if (N1.getOpcode() == ISD::ZERO_EXTEND_INREG)
+ return getNode(ISD::ZERO_EXTEND, VT, Tmp);
+ else
+ return getNode(ISD::SIGN_EXTEND, VT, Tmp);
+ }
+
// If we are sign extending an extension, use the original source.
if (N1.getOpcode() == ISD::ZERO_EXTEND_INREG ||
N1.getOpcode() == ISD::SIGN_EXTEND_INREG) {