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Change the copy.i* function to reverse.i*
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@nickg
nickg committed Aug 15, 2012
1 parent c3f00cb commit 701bdf5
Showing 1 changed file with 47 additions and 77 deletions.
124 changes: 47 additions & 77 deletions src/cgen.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,7 +74,7 @@ static LLVMValueRef cgen_get_var(tree_t decl, cgen_ctx_t *ctx);
static bool cgen_const_bounds(type_t type);
static LLVMValueRef cgen_array_data_ptr(type_t type, LLVMValueRef var);
static LLVMTypeRef cgen_signal_type(type_t type);
static void cgen_array_copy_fn(type_t type);
static void cgen_array_reverse_fn(type_t type);

static LLVMValueRef llvm_int1(bool b)
{
Expand Down Expand Up @@ -565,7 +565,7 @@ static void cgen_array_copy(type_t src_type, type_t dest_type,
LLVMValueRef src, LLVMValueRef dst,
LLVMValueRef offset, cgen_ctx_t *ctx)
{
cgen_array_copy_fn(src_type);
cgen_array_reverse_fn(src_type);

LLVMValueRef src_dir = cgen_array_dir(src_type, src);
LLVMValueRef dst_dir = cgen_array_dir(dest_type, dst);
Expand All @@ -587,31 +587,32 @@ static void cgen_array_copy(type_t src_type, type_t dest_type,
(cgen_const_bounds(src_type) && cgen_const_bounds(dest_type)
&& (type_dim(src_type, 0).kind == type_dim(dest_type, 0).kind));

if (same_dir_const) {
// Fast path: use LLVM memcpy
int width = bit_width(src_type);

int width = bit_width(src_type);
char memcpy_name[128];
snprintf(memcpy_name, sizeof(memcpy_name),
"llvm.memcpy.p0i%d.p0i%d.i32", width, width);

char name[128];
snprintf(name, sizeof(name),
"llvm.memcpy.p0i%d.p0i%d.i32", width, width);
int bytes = (width / 8) + ((width % 8 > 0) ? 1 : 0);
LLVMValueRef size = LLVMBuildMul(builder, ll_n_elems,
llvm_int32(bytes), "size");

int bytes = (width / 8) + ((width % 8 > 0) ? 1 : 0);
LLVMValueRef size = LLVMBuildMul(builder, ll_n_elems,
llvm_int32(bytes), "size");
LLVMValueRef indexes[] = { offset };
LLVMValueRef dst_ptr = LLVMBuildGEP(builder, dst, indexes,
ARRAY_LEN(indexes), "dst_ptr");

LLVMValueRef indexes[] = { offset };
LLVMValueRef dst_ptr = LLVMBuildGEP(builder, dst, indexes,
ARRAY_LEN(indexes), "dst_ptr");
LLVMValueRef memcpy_args[] = {
dst_ptr,
src_ptr,
size,
llvm_int32(bytes),
llvm_int1(0)
};

LLVMValueRef args[] = {
dst_ptr,
src_ptr,
size,
llvm_int32(bytes),
llvm_int1(0)
};
LLVMBuildCall(builder, llvm_fn(name), args, ARRAY_LEN(args), "");
if (same_dir_const) {
// Fast path: use LLVM memcpy
LLVMBuildCall(builder, llvm_fn(memcpy_name),
memcpy_args, ARRAY_LEN(memcpy_args), "");
}
else {
LLVMBasicBlockRef fast_bb = LLVMAppendBasicBlock(ctx->fn, "fast");
Expand All @@ -620,33 +621,19 @@ static void cgen_array_copy(type_t src_type, type_t dest_type,

LLVMBuildCondBr(builder, opposite_dir, slow_bb, fast_bb);

// Fast(ish) path: use per-type copy function
// Fast(ish) path: call LLVM memcpy after condition

LLVMPositionBuilderAtEnd(builder, fast_bb);
LLVMBuildCall(builder, llvm_fn(memcpy_name),
memcpy_args, ARRAY_LEN(memcpy_args), "");
LLVMBuildBr(builder, done_bb);

{
int width = bit_width(type_elem(dest_type));

char name[128];
snprintf(name, sizeof(name), "copy.i%d", width);

LLVMValueRef args[] = {
dst,
src_ptr,
offset,
ll_n_elems,
opposite_dir
};
LLVMBuildCall(builder, llvm_fn(name), args, ARRAY_LEN(args), "");

LLVMBuildBr(builder, done_bb);
}

// Slow path: call _array_copy helper
// Slow path: call reverse.iN helper function

LLVMPositionBuilderAtEnd(builder, slow_bb);

{
#if 0
LLVMValueRef args[] = {
llvm_void_cast(dst),
llvm_void_cast(src_ptr),
Expand All @@ -657,6 +644,21 @@ static void cgen_array_copy(type_t src_type, type_t dest_type,
};
LLVMBuildCall(builder, llvm_fn("_array_copy"),
args, ARRAY_LEN(args), "");
#else
int width = bit_width(type_elem(dest_type));

char name[128];
snprintf(name, sizeof(name), "reverse.i%d", width);

LLVMValueRef args[] = {
dst,
src_ptr,
offset,
ll_n_elems,
opposite_dir
};
LLVMBuildCall(builder, llvm_fn(name), args, ARRAY_LEN(args), "");
#endif

LLVMBuildBr(builder, done_bb);
}
Expand Down Expand Up @@ -2518,17 +2520,17 @@ static LLVMValueRef cgen_signal_init(type_t type)
}
}

static void cgen_array_copy_fn(type_t elem_type)
static void cgen_array_reverse_fn(type_t elem_type)
{
// Build a function to copy one array into another
// Build a function to reverse one array into another

while (type_is_array(elem_type))
elem_type = type_elem(elem_type);

int width = bit_width(elem_type);

char name[256];
snprintf(name, sizeof(name), "copy.i%d", width);
snprintf(name, sizeof(name), "reverse.i%d", width);

LLVMValueRef fn;
if ((fn = LLVMGetNamedFunction(module, name)))
Expand All @@ -2554,8 +2556,6 @@ static void cgen_array_copy_fn(type_t elem_type)
LLVMAddAttribute(LLVMGetParam(fn, 1), LLVMNoCaptureAttribute);

LLVMBasicBlockRef entry_bb = LLVMAppendBasicBlock(fn, "entry");
LLVMBasicBlockRef mcpy_bb = LLVMAppendBasicBlock(fn, "mcpy");
LLVMBasicBlockRef loop_bb = LLVMAppendBasicBlock(fn, "loop");
LLVMBasicBlockRef test_bb = LLVMAppendBasicBlock(fn, "test");
LLVMBasicBlockRef body_bb = LLVMAppendBasicBlock(fn, "body");
LLVMBasicBlockRef exit_bb = LLVMAppendBasicBlock(fn, "exit");
Expand All @@ -2568,37 +2568,7 @@ static void cgen_array_copy_fn(type_t elem_type)

LLVMValueRef src_ptr = LLVMGetParam(fn, 1);

// Check if we're reversing the array

LLVMValueRef reverse = LLVMGetParam(fn, 4);
LLVMBuildCondBr(builder, reverse, loop_bb, mcpy_bb);

// Just call memcpy if not reversing

LLVMPositionBuilderAtEnd(builder, mcpy_bb);

char memcpy_name[128];
snprintf(memcpy_name, sizeof(memcpy_name),
"llvm.memcpy.p0i%d.p0i%d.i32", width, width);

int bytes = (width / 8) + ((width % 8 > 0) ? 1 : 0);
LLVMValueRef size = LLVMBuildMul(builder, LLVMGetParam(fn, 3),
llvm_int32(bytes), "size");

LLVMValueRef memcpy_args[] = {
dst_ptr,
src_ptr,
size,
llvm_int32(width),
llvm_int1(0)
};
LLVMBuildCall(builder, llvm_fn(memcpy_name),
memcpy_args, ARRAY_LEN(memcpy_args), "");

LLVMBuildBr(builder, exit_bb);

// Prelude
LLVMPositionBuilderAtEnd(builder, loop_bb);
LLVMValueRef n_sub_1 = LLVMBuildSub(builder, LLVMGetParam(fn, 3),
llvm_int32(1), "n_sub_1");
LLVMValueRef i = LLVMBuildAlloca(builder, LLVMInt32Type(), "i");
Expand Down

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