[PATCH v1] RISC-V: Take Xmode instead of Pmode for ussub expanding

[pan2 . li]

From: Pan Li <pan2...@intel.com>

The Pmode is designed for pointer,  thus leverage the Xmode instead
for the expanding of the ussub.

gcc/ChangeLog:

        * config/riscv/riscv.cc (riscv_expand_ussub): Promote to Xmode
        instead of Pmode.

Signed-off-by: Pan Li <pan2...@intel.com>
---
 gcc/config/riscv/riscv.cc | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index a490b9598b0..8ece7859945 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -11620,26 +11620,26 @@ void
 riscv_expand_ussub (rtx dest, rtx x, rtx y)
 {
   machine_mode mode = GET_MODE (dest);
-  rtx pmode_x = gen_lowpart (Pmode, x);
-  rtx pmode_y = gen_lowpart (Pmode, y);
-  rtx pmode_lt = gen_reg_rtx (Pmode);
-  rtx pmode_minus = gen_reg_rtx (Pmode);
-  rtx pmode_dest = gen_reg_rtx (Pmode);
+  rtx xmode_x = gen_lowpart (Xmode, x);
+  rtx xmode_y = gen_lowpart (Xmode, y);
+  rtx xmode_lt = gen_reg_rtx (Xmode);
+  rtx xmode_minus = gen_reg_rtx (Xmode);
+  rtx xmode_dest = gen_reg_rtx (Xmode);
 
   /* Step-1: minus = x - y  */
-  riscv_emit_binary (MINUS, pmode_minus, pmode_x, pmode_y);
+  riscv_emit_binary (MINUS, xmode_minus, xmode_x, xmode_y);
 
   /* Step-2: lt = x < y  */
-  riscv_emit_binary (LTU, pmode_lt, pmode_x, pmode_y);
+  riscv_emit_binary (LTU, xmode_lt, xmode_x, xmode_y);
 
   /* Step-3: lt = lt - 1 (lt + (-1))  */
-  riscv_emit_binary (PLUS, pmode_lt, pmode_lt, CONSTM1_RTX (Pmode));
+  riscv_emit_binary (PLUS, xmode_lt, xmode_lt, CONSTM1_RTX (Xmode));
 
-  /* Step-4: pmode_dest = minus & lt  */
-  riscv_emit_binary (AND, pmode_dest, pmode_lt, pmode_minus);
+  /* Step-4: xmode_dest = minus & lt  */
+  riscv_emit_binary (AND, xmode_dest, xmode_lt, xmode_minus);
 
-  /* Step-5: dest = pmode_dest  */
-  emit_move_insn (dest, gen_lowpart (mode, pmode_dest));
+  /* Step-5: dest = xmode_dest  */
+  emit_move_insn (dest, gen_lowpart (mode, xmode_dest));
 }
 
 /* Implement the unsigned saturation truncation for int mode.
-- 
2.34.1