Two improvements:
1. Codegen this comparison:
if (X == 0x8000)
as:
cmplwi cr0, r3, 32768
bne cr0, LBB1_2 ;cond_next
instead of:
lis r2, 0
ori r2, r2, 32768
cmpw cr0, r3, r2
bne cr0, LBB1_2 ;cond_next
2. Codegen this comparison:
if (X == 0x12345678)
as:
xoris r2, r3, 4660
cmplwi cr0, r2, 22136
bne cr0, LBB1_2 ;cond_next
instead of:
lis r2, 4660
ori r2, r2, 22136
cmpw cr0, r3, r2
bne cr0, LBB1_2 ;cond_next
llvm-svn: 30509
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 4662e53..70b2aa0 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -699,7 +699,33 @@
if (LHS.getValueType() == MVT::i32) {
unsigned Imm;
- if (ISD::isUnsignedIntSetCC(CC)) {
+ if (CC == ISD::SETEQ || CC == ISD::SETNE) {
+ if (isInt32Immediate(RHS, Imm)) {
+ // SETEQ/SETNE comparison with 16-bit immediate, fold it.
+ if (isUInt16(Imm))
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, LHS,
+ getI32Imm(Imm & 0xFFFF)), 0);
+ // If this is a 16-bit signed immediate, fold it.
+ if (isInt16(Imm))
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPWI, MVT::i32, LHS,
+ getI32Imm(Imm & 0xFFFF)), 0);
+
+ // For non-equality comparisons, the default code would materialize the
+ // constant, then compare against it, like this:
+ // lis r2, 4660
+ // ori r2, r2, 22136
+ // cmpw cr0, r3, r2
+ // Since we are just comparing for equality, we can emit this instead:
+ // xoris r0,r3,0x1234
+ // cmplwi cr0,r0,0x5678
+ // beq cr0,L6
+ SDOperand Xor(CurDAG->getTargetNode(PPC::XORIS, MVT::i32, LHS,
+ getI32Imm(Imm >> 16)), 0);
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, Xor,
+ getI32Imm(Imm & 0xFFFF)), 0);
+ }
+ Opc = PPC::CMPLW;
+ } else if (ISD::isUnsignedIntSetCC(CC)) {
if (isInt32Immediate(RHS, Imm) && isUInt16(Imm))
return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, LHS,
getI32Imm(Imm & 0xFFFF)), 0);
diff --git a/llvm/lib/Target/PowerPC/README.txt b/llvm/lib/Target/PowerPC/README.txt
index cfc7eb38..4f7f2cf 100644
--- a/llvm/lib/Target/PowerPC/README.txt
+++ b/llvm/lib/Target/PowerPC/README.txt
@@ -50,27 +50,6 @@
===-------------------------------------------------------------------------===
-* Codegen this:
-
- void test2(int X) {
- if (X == 0x12345678) bar();
- }
-
- as:
-
- xoris r0,r3,0x1234
- cmplwi cr0,r0,0x5678
- beq cr0,L6
-
- not:
-
- lis r2, 4660
- ori r2, r2, 22136
- cmpw cr0, r3, r2
- bne .LBB_test2_2
-
-===-------------------------------------------------------------------------===
-
Lump the constant pool for each function into ONE pic object, and reference
pieces of it as offsets from the start. For functions like this (contrived
to have lots of constants obviously):