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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
View File

@ -1842,28 +1842,6 @@ simplify_context::simplify_unary_operation_1 (rtx_code code, machine_mode mode,
& ~GET_MODE_MASK (op_mode)) == 0)
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)
/* 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

14
gcc/testsuite/gcc.target/riscv/pr112398.c
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@ -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" } } */