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
2 files changed