Finally pass "two floats in a 64-bit unit" as a <2 x float> instead of

as a double in the x86-64 ABI.  This allows us to generate much better
code for certain things, e.g.:

_Complex float f32(_Complex float A, _Complex float B) {
  return A+B;
}

Used to compile into (look at the integer silliness!):

_f32:                                   ## @f32
## BB#0:                                ## %entry
	movd	%xmm1, %rax
	movd	%eax, %xmm1
	movd	%xmm0, %rcx
	movd	%ecx, %xmm0
	addss	%xmm1, %xmm0
	movd	%xmm0, %edx
	shrq	$32, %rax
	movd	%eax, %xmm0
	shrq	$32, %rcx
	movd	%ecx, %xmm1
	addss	%xmm0, %xmm1
	movd	%xmm1, %eax
	shlq	$32, %rax
	addq	%rdx, %rax
	movd	%rax, %xmm0
	ret

Now we get:

_f32:                                   ## @f32
	movdqa	%xmm0, %xmm2
	addss	%xmm1, %xmm2
	pshufd	$16, %xmm2, %xmm2
	pshufd	$1, %xmm1, %xmm1
	pshufd	$1, %xmm0, %xmm0
	addss	%xmm1, %xmm0
	pshufd	$16, %xmm0, %xmm1
	movdqa	%xmm2, %xmm0
	unpcklps	%xmm1, %xmm0
	ret

and compile stuff like:

extern float _Complex ccoshf( float _Complex ) ;
float _Complex ccosf ( float _Complex z ) {
 float _Complex iz;
 (__real__ iz) = -(__imag__ z);
 (__imag__ iz) = (__real__ z);
 return ccoshf(iz);
}

into:

_ccosf:                                 ## @ccosf
## BB#0:                                ## %entry
	pshufd	$1, %xmm0, %xmm1
	xorps	LCPI4_0(%rip), %xmm1
	unpcklps	%xmm0, %xmm1
	movaps	%xmm1, %xmm0
	jmp	_ccoshf                 ## TAILCALL

instead of:

_ccosf:                                 ## @ccosf
## BB#0:                                ## %entry
	movd	%xmm0, %rax
	movq	%rax, %rcx
	shlq	$32, %rcx
	shrq	$32, %rax
	xorl	$-2147483648, %eax      ## imm = 0xFFFFFFFF80000000
	addq	%rcx, %rax
	movd	%rax, %xmm0
	jmp	_ccoshf                 ## TAILCALL


There is still "stuff to be done" here for the struct case,
but this resolves rdar://6379669 - [x86-64 ABI] Pass and return 
_Complex float / double efficiently



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112111 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 6 deletions

diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index a08e7f4b80..c5b858dbfa 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -1294,12 +1294,8 @@ GetSSETypeAtOffset(const llvm::Type *IRType, unsigned IROffset,
   // offset+0 and offset+4.  Walk the LLVM IR type to find out if this is the
   // case.
   if (ContainsFloatAtOffset(IRType, IROffset, getTargetData()) &&
-      ContainsFloatAtOffset(IRType, IROffset+4, getTargetData())) {
-    // FIXME: <2 x float> doesn't pass as one XMM register yet.  Don't enable
-    // this code until it does.
-    //return llvm::VectorType::get(llvm::Type::getFloatTy(getVMContext()), 2);
-
-  }
+      ContainsFloatAtOffset(IRType, IROffset+4, getTargetData()))
+    return llvm::VectorType::get(llvm::Type::getFloatTy(getVMContext()), 2);
 
   return llvm::Type::getDoubleTy(getVMContext());
 }