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Revert "Reapply "[PATCH v2] RISC-V: zero_extend(not) -> xor optimization [PR112398]""

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This reverts commit 10d76b7f1e.
This commit is contained in:
Jeff Law 2024-11-14 09:26:11 -07:00
parent 4bce1f71c9
commit 72677e1119
2 changed files with 0 additions and 36 deletions
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22
gcc/simplify-rtx.cc
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@ -1842,28 +1842,6 @@ simplify_context::simplify_unary_operation_1 (rtx_code code, machine_mode mode,
& ~GET_MODE_MASK (op_mode)) == 0) & ~GET_MODE_MASK (op_mode)) == 0)
return SUBREG_REG (op); return SUBREG_REG (op);
/* Trying to optimize:
(zero_extend:M (subreg:N (not:M (X:M)))) ->
(xor:M (zero_extend:M (subreg:N (X:M)), mask))
where the mask is GET_MODE_MASK (N).
For the cases when X:M doesn't have any non-zero bits
outside of mode N, (zero_extend:M (subreg:N (X:M))
will be simplified to just (X:M)
and whole optimization will be -> (xor:M (X:M, mask)). */
if (SUBREG_P (op)
&& GET_CODE (XEXP (op, 0)) == NOT
&& GET_MODE (XEXP (op, 0)) == mode
&& subreg_lowpart_p (op)
&& GET_MODE_SIZE (GET_MODE (op)).is_constant ()
&& (nonzero_bits (XEXP (XEXP (op, 0), 0), mode)
& ~GET_MODE_MASK (mode)) == 0)
{
const uint64_t mask = GET_MODE_MASK (GET_MODE (op));
return simplify_gen_binary (XOR, mode,
XEXP (XEXP (op, 0), 0),
gen_int_mode (mask, mode));
}
#if defined(POINTERS_EXTEND_UNSIGNED) #if defined(POINTERS_EXTEND_UNSIGNED)
/* As we do not know which address space the pointer is referring to, /* As we do not know which address space the pointer is referring to,
we can do this only if the target does not support different pointer we can do this only if the target does not support different pointer

14
gcc/testsuite/gcc.target/riscv/pr112398.c
View File

@ -1,14 +0,0 @@
/* { dg-do compile } */
/* { dg-options "-march=rv64gc -mabi=lp64d" } */
/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
#include <stdint.h>
uint8_t neg_u8 (const uint8_t src)
{
return ~src;
}
/* { dg-final { scan-assembler-times "xori\t" 1 } } */
/* { dg-final { scan-assembler-not "not\t" } } */
/* { dg-final { scan-assembler-not "andi\t" } } */