[gcc r14-4175] RISC-V: Support simplifying x/(-1) to neg for vector.

[Pan Li <panli@gcc.gnu.org>]

https://gcc.gnu.org/g:b9cb735fc1bb4ca2339ab900e2d07667d7c0f6b4

commit r14-4175-gb9cb735fc1bb4ca2339ab900e2d07667d7c0f6b4
Author: Yanzhang Wang <yanzhang.wang@intel.com>
Date:   Wed Sep 20 11:36:20 2023 +0800

    RISC-V: Support simplifying x/(-1) to neg for vector.
    
    gcc/ChangeLog:
    
            * simplify-rtx.cc (simplify_context::simplify_binary_operation_1):
            support simplifying vector int not only scalar int.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/riscv/rvv/base/simplify-vdiv.c: New test.
    
    Signed-off-by: Yanzhang Wang <yanzhang.wang@intel.com>

Diff:
---
 gcc/simplify-rtx.cc                                    |  4 ++--
 .../gcc.target/riscv/rvv/base/simplify-vdiv.c          | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index eb1ac120832..170406aa28b 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -4093,7 +4093,7 @@ simplify_context::simplify_binary_operation_1 (rtx_code code,
 		}
 	    }
 	}
-      else if (SCALAR_INT_MODE_P (mode))
+      else if (SCALAR_INT_MODE_P (mode) || GET_MODE_CLASS (mode) == MODE_VECTOR_INT)
 	{
 	  /* 0/x is 0 (or x&0 if x has side-effects).  */
 	  if (trueop0 == CONST0_RTX (mode)
@@ -4111,7 +4111,7 @@ simplify_context::simplify_binary_operation_1 (rtx_code code,
 		return tem;
 	    }
 	  /* x/-1 is -x.  */
-	  if (trueop1 == constm1_rtx)
+	  if (trueop1 == CONSTM1_RTX (mode))
 	    {
 	      rtx x = rtl_hooks.gen_lowpart_no_emit (mode, op0);
 	      if (x)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/simplify-vdiv.c b/gcc/testsuite/gcc.target/riscv/rvv/base/simplify-vdiv.c
new file mode 100644
index 00000000000..08300061832
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/simplify-vdiv.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64 -O3 -Wno-psabi" } */
+
+#include "riscv_vector.h"
+
+#define VDIV_WITH_LMUL(LMUL, DTYPE)                        \
+  vint##DTYPE##m##LMUL##_t                                  \
+  shortcut_for_riscv_vdiv_case_##LMUL##_##DTYPE            \
+  (vint##DTYPE##m##LMUL##_t v1,                             \
+   size_t vl)                                               \
+  {                                                         \
+    return __riscv_vdiv_vx_i##DTYPE##m##LMUL (v1, -1, vl); \
+  }
+
+VDIV_WITH_LMUL (1, 16)
+VDIV_WITH_LMUL (1, 32)
+
+/* { dg-final { scan-assembler-times {vneg\.v} 2 } } */