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authorChris Lattner <sabre@nondot.org>2005-01-12 02:19:06 +0000
committerChris Lattner <sabre@nondot.org>2005-01-12 02:19:06 +0000
commitafce4306ec9d9ce5def7c3697654f3bcbbeb5cb9 (patch)
tree14909dd771573c457a429ee67f09cf25b64a0965
parentef6806c979fa6829227dda5f25ef9f2b57c7e762 (diff)
Fold TRUNCATE (LOAD P) into a smaller load from P.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19494 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Target/X86/X86ISelPattern.cpp15
1 files changed, 15 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelPattern.cpp b/lib/Target/X86/X86ISelPattern.cpp
index dacd5133c1..34d1356470 100644
--- a/lib/Target/X86/X86ISelPattern.cpp
+++ b/lib/Target/X86/X86ISelPattern.cpp
@@ -410,6 +410,7 @@ unsigned ISel::ComputeRegPressure(SDOperand O) {
Result = MaxRegUse+NumExtraMaxRegUsers;
}
+
//std::cerr << " WEIGHT: " << Result << " "; N->dump(); std::cerr << "\n";
return Result;
}
@@ -1106,6 +1107,20 @@ unsigned ISel::SelectExpr(SDOperand N) {
return Result;
}
case ISD::TRUNCATE:
+ // Fold TRUNCATE (LOAD P) into a smaller load from P.
+ if (isFoldableLoad(N.getOperand(0))) {
+ switch (N.getValueType()) {
+ default: assert(0 && "Unknown truncate!");
+ case MVT::i1:
+ case MVT::i8: Opc = X86::MOV8rm; break;
+ case MVT::i16: Opc = X86::MOV16rm; break;
+ }
+ X86AddressMode AM;
+ EmitFoldedLoad(N.getOperand(0), AM);
+ addFullAddress(BuildMI(BB, Opc, 4, Result), AM);
+ return Result;
+ }
+
// Handle cast of LARGER int to SMALLER int using a move to EAX followed by
// a move out of AX or AL.
switch (N.getOperand(0).getValueType()) {