CodeGenPrep: sink extends of illegal types into use block.
Summary:
This helps the instruction selector to lower an i64 * i64 -> i128
multiplication into a single instruction on targets which support it.
This is an update of D2973 which was reverted because of a bug reported
as PR19084.
Reviewers: t.p.northover, chapuni
Reviewed By: t.p.northover
CC: llvm-commits, alex, chapuni
Differential Revision: http://llvm-reviews.chandlerc.com/D3021
llvm-svn: 203797
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index d53cdb9..428d8af 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -464,40 +464,8 @@
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
}
-/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
-/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
-/// sink it into user blocks to reduce the number of virtual
-/// registers that must be created and coalesced.
-///
-/// Return true if any changes are made.
-///
-static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
- // If this is a noop copy,
- EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
- EVT DstVT = TLI.getValueType(CI->getType());
-
- // This is an fp<->int conversion?
- if (SrcVT.isInteger() != DstVT.isInteger())
- return false;
-
- // If this is an extension, it will be a zero or sign extension, which
- // isn't a noop.
- if (SrcVT.bitsLT(DstVT)) return false;
-
- // If these values will be promoted, find out what they will be promoted
- // to. This helps us consider truncates on PPC as noop copies when they
- // are.
- if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
- TargetLowering::TypePromoteInteger)
- SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
- if (TLI.getTypeAction(CI->getContext(), DstVT) ==
- TargetLowering::TypePromoteInteger)
- DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
-
- // If, after promotion, these are the same types, this is a noop copy.
- if (SrcVT != DstVT)
- return false;
-
+/// SinkCast - Sink the specified cast instruction into its user blocks
+static bool SinkCast(CastInst *CI) {
BasicBlock *DefBB = CI->getParent();
/// InsertedCasts - Only insert a cast in each block once.
@@ -547,6 +515,43 @@
return MadeChange;
}
+/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
+/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
+/// sink it into user blocks to reduce the number of virtual
+/// registers that must be created and coalesced.
+///
+/// Return true if any changes are made.
+///
+static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
+ // If this is a noop copy,
+ EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
+ EVT DstVT = TLI.getValueType(CI->getType());
+
+ // This is an fp<->int conversion?
+ if (SrcVT.isInteger() != DstVT.isInteger())
+ return false;
+
+ // If this is an extension, it will be a zero or sign extension, which
+ // isn't a noop.
+ if (SrcVT.bitsLT(DstVT)) return false;
+
+ // If these values will be promoted, find out what they will be promoted
+ // to. This helps us consider truncates on PPC as noop copies when they
+ // are.
+ if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
+ TargetLowering::TypePromoteInteger)
+ SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
+ if (TLI.getTypeAction(CI->getContext(), DstVT) ==
+ TargetLowering::TypePromoteInteger)
+ DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
+
+ // If, after promotion, these are the same types, this is a noop copy.
+ if (SrcVT != DstVT)
+ return false;
+
+ return SinkCast(CI);
+}
+
/// OptimizeCmpExpression - sink the given CmpInst into user blocks to reduce
/// the number of virtual registers that must be created and coalesced. This is
/// a clear win except on targets with multiple condition code registers
@@ -2811,8 +2816,16 @@
return true;
if (isa<ZExtInst>(I) || isa<SExtInst>(I)) {
- bool MadeChange = MoveExtToFormExtLoad(I);
- return MadeChange | OptimizeExtUses(I);
+ /// Sink a zext or sext into its user blocks if the target type doesn't
+ /// fit in one register
+ if (TLI && TLI->getTypeAction(CI->getContext(),
+ TLI->getValueType(CI->getType())) ==
+ TargetLowering::TypeExpandInteger) {
+ return SinkCast(CI);
+ } else {
+ bool MadeChange = MoveExtToFormExtLoad(I);
+ return MadeChange | OptimizeExtUses(I);
+ }
}
return false;
}