[PATCH] D50979: Eliminate instances of `EmitScalarExpr(E->getArg(n))` in EmitX86BuiltinExpr().

[Nico Weber via Phabricator via cfe-commits]

thakis created this revision.
thakis added a reviewer: rnk.
Herald added a reviewer: javed.absar.
Herald added a subscriber: kristof.beyls.

EmitX86BuiltinExpr() emits all args into Ops at the beginning, so don't do that work again. No intended behavior change.

(TNorthover: EmitAArch64BuiltinExpr() also emits args into Ops before the big switch (with some more subtlety around the last arg that I don't understand), but then almost every switch case does `EmitScalarExpr(E->getArg(n))`. It's been like this since the commit that added the arm64 code. Was the Ops pushing code added later and all the EmitScalarExpr()s are now unneeded, or is some reason for this?)


https://reviews.llvm.org/D50979

Files:
  clang/lib/CodeGen/CGBuiltin.cpp


Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -10480,14 +10480,11 @@
     llvm::Type *Int128PtrTy = Int128Ty->getPointerTo();
 
     Value *Destination =
-        Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)), Int128PtrTy);
-    Value *ExchangeHigh128 =
-        Builder.CreateZExt(EmitScalarExpr(E->getArg(1)), Int128Ty);
-    Value *ExchangeLow128 =
-        Builder.CreateZExt(EmitScalarExpr(E->getArg(2)), Int128Ty);
-    Address ComparandResult(
-        Builder.CreateBitCast(EmitScalarExpr(E->getArg(3)), Int128PtrTy),
-        getContext().toCharUnitsFromBits(128));
+        Builder.CreateBitCast(Ops[0], Int128PtrTy);
+    Value *ExchangeHigh128 = Builder.CreateZExt(Ops[1], Int128Ty);
+    Value *ExchangeLow128 = Builder.CreateZExt(Ops[2], Int128Ty);
+    Address ComparandResult(Builder.CreateBitCast(Ops[3], Int128PtrTy),
+                            getContext().toCharUnitsFromBits(128));
 
     Value *Exchange = Builder.CreateOr(
         Builder.CreateShl(ExchangeHigh128, 64, "", false, false),
@@ -10538,8 +10535,8 @@
   case X86::BI__readfsdword:
   case X86::BI__readfsqword: {
     llvm::Type *IntTy = ConvertType(E->getType());
-    Value *Ptr = Builder.CreateIntToPtr(EmitScalarExpr(E->getArg(0)),
-                                        llvm::PointerType::get(IntTy, 257));
+    Value *Ptr =
+        Builder.CreateIntToPtr(Ops[0], llvm::PointerType::get(IntTy, 257));
     LoadInst *Load = Builder.CreateAlignedLoad(
         IntTy, Ptr, getContext().getTypeAlignInChars(E->getType()));
     Load->setVolatile(true);
@@ -10550,8 +10547,8 @@
   case X86::BI__readgsdword:
   case X86::BI__readgsqword: {
     llvm::Type *IntTy = ConvertType(E->getType());
-    Value *Ptr = Builder.CreateIntToPtr(EmitScalarExpr(E->getArg(0)),
-                                        llvm::PointerType::get(IntTy, 256));
+    Value *Ptr =
+        Builder.CreateIntToPtr(Ops[0], llvm::PointerType::get(IntTy, 256));
     LoadInst *Load = Builder.CreateAlignedLoad(
         IntTy, Ptr, getContext().getTypeAlignInChars(E->getType()));
     Load->setVolatile(true);


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