procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Prefer scalar_int_mode if the size - 1 is equal to UNITS_PER_WORD.

Browse source 
Don't use the QI vector if its size is equal to UNITS_PER_WORD for
better code generation.

Before patch:

vsetivli        zero,4,e8,mf4,ta,ma
vmv.v.i v1,0
addi    a4,sp,12
vse8.v  v1,0(a4)

After patch:

sw      zero,12(sp)

gcc/
	* expr.cc (widest_fixed_size_mode_for_size): Prefer scalar modes
	over vector modes in more cases.

gcc/testsuite/

	* gcc.target/riscv/rvv/autovec/pr113469.c: Update expected output.
	* gcc.target/riscv/rvv/base/movqi-1.c: New test.
This commit is contained in:
Tsung Chun Lin 2025-01-07 14:48:31 -07:00 • committed by Jeff Law
parent c6b5398e9e
commit d953c2c571
3 changed files with 20 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
gcc/expr.cc
View file

@ -1062,12 +1062,13 @@ widest_fixed_size_mode_for_size (unsigned int size, by_pieces_operation op)
gcc_checking_assert (size > 1);
/* Use QI vector only if size is wider than a WORD. */
if (can_use_qi_vectors (op) && size > UNITS_PER_WORD)
if (can_use_qi_vectors (op))
{
machine_mode mode;
fixed_size_mode candidate;
FOR_EACH_MODE_IN_CLASS (mode, MODE_VECTOR_INT)
if (is_a<fixed_size_mode> (mode, &candidate)
&& GET_MODE_SIZE (candidate) > UNITS_PER_WORD
&& GET_MODE_INNER (candidate) == QImode)
{
if (GET_MODE_SIZE (candidate) >= size)

1
gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113469.c
View file

@ -51,5 +51,4 @@ void p(int buf, __builtin_va_list ab, int q) {
} while (k);
}
/* { dg-final { scan-assembler-times {vsetivli\tzero,\s*4,\s*e8,\s*mf4,\s*t[au],\s*m[au]} 1 } } */
/* { dg-final { scan-assembler-times {vsetivli\tzero,\s*8,\s*e8,\s*mf2,\s*t[au],\s*m[au]} 1 } } */

18
gcc/testsuite/gcc.target/riscv/rvv/base/movqi-1.c Normal file
View file

@ -0,0 +1,18 @@
/* Test that we do not use QI vector to initilize the memory if the
* size of QI vector isn't larger than UNITS_PER_WORD */
/* { dg-do compile } */
/* { dg-options "-march=rv32gcv -mabi=ilp32 -O3" } */
struct s {
int a;
int b : 1;
};
void q(struct s*);
void g() {
struct s r = { 15, 0 };
q(&r);
}
/* { dg-final { scan-assembler-times {sw\tzero,12\(sp\)} 1 } } */