From 72677e1119dc40aa680755d009e079ad49446c46 Mon Sep 17 00:00:00 2001
From: Jeff Law <jlaw@ventanamicro.com>
Date: Thu, 14 Nov 2024 09:26:11 -0700
Subject: [PATCH] Revert "Reapply "[PATCH v2] RISC-V: zero_extend(not) -> xor
 optimization [PR112398]""

This reverts commit 10d76b7f1e5b63ad6d2b92940c39007913ced037.
---
 gcc/simplify-rtx.cc                       | 22 ----------------------
 gcc/testsuite/gcc.target/riscv/pr112398.c | 14 --------------
 2 files changed, 36 deletions(-)
 delete mode 100644 gcc/testsuite/gcc.target/riscv/pr112398.c

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index d05efac20dc..893c5f6e1ae 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -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
diff --git a/gcc/testsuite/gcc.target/riscv/pr112398.c b/gcc/testsuite/gcc.target/riscv/pr112398.c
deleted file mode 100644
index 624a665b76c..00000000000
--- a/gcc/testsuite/gcc.target/riscv/pr112398.c
+++ /dev/null
@@ -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" } } */