From: Pan Li <pan2...@intel.com>
This patch would like to refactor the helper function of the SAT_*
scalar. The helper function will convert the define_pattern ops
to the xmode reg for the underlying code-gen. This patch add
new parameter for ZERO_EXTEND or SIGN_EXTEND if the input is const_int
or the mode is non-Xmode.
The below test suites are passed for this patch.
* The rv64gcv fully regression test.
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_gen_zero_extend_rtx): Rename from ...
(riscv_extend_to_xmode_reg): Rename to and add rtx_code for
zero/sign extend if non-Xmode.
(riscv_expand_usadd): Leverage the renamed function with ZERO_EXTEND.
(riscv_expand_ussub): Ditto.
Signed-off-by: Pan Li <pan2...@intel.com>
---
gcc/config/riscv/riscv.cc | 61 +++++++++++++++++++++++----------------
1 file changed, 36 insertions(+), 25 deletions(-)
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 5a3a0504177..3b9a2c5500d 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -12639,17 +12639,29 @@ riscv_get_raw_result_mode (int regno)
return default_get_reg_raw_mode (regno);
}
-/* Generate a REG rtx of Xmode from the given rtx and mode.
+/* Generate a REG rtx of Xmode from the given rtx and rtx_code.
The rtx x can be REG (QI/HI/SI/DI) or const_int.
The machine_mode mode is the original mode from define pattern.
+ The rtx_code can be ZERO_EXTEND or SIGN_EXTEND.
- If rtx is REG and Xmode, the RTX x will be returned directly.
+ If rtx is REG:
- If rtx is REG and non-Xmode, the zero extended to new REG of Xmode will be
- returned.
+ 1. If rtx Xmode, the RTX x will be returned directly.
+ 2. if rtx non-Xmode, the extended to new REG of Xmode will be returned.
- If rtx is const_int, a new REG rtx will be created to hold the value of
- const_int and then returned.
+ The scalar ALU like add don't support non-Xmode like QI/HI. Then the
+ gen_lowpart will have problem here. For example, when we would like
+ to add -1(0xff if QImode) and 2(0x2 if QImode). The 0xff and 0x2 will
+ be loaded to register for adding. Aka:
+
+ 0xff + 0x2 = 0x101 instead of -1 + 2 = 1.
+
+ Thus we need to sign extend 0xff to 0xffffffffffffffff if Xmode is DImode
+ for correctness. Similar the unsigned also need zero extend.
+
+ If rtx is const_int:
+
+ 1. A new REG rtx will be created to hold the value of const_int.
According to the gccint doc, the constants generated for modes with fewer
bits than in HOST_WIDE_INT must be sign extended to full width. Thus there
@@ -12667,28 +12679,27 @@ riscv_get_raw_result_mode (int regno)
the REG rtx of Xmode, instead of taking care of these in expand func. */
static rtx
-riscv_gen_zero_extend_rtx (rtx x, machine_mode mode)
+riscv_extend_to_xmode_reg (rtx x, machine_mode mode, enum rtx_code rcode)
{
+ gcc_assert (rcode == ZERO_EXTEND || rcode == SIGN_EXTEND);
+
rtx xmode_reg = gen_reg_rtx (Xmode);
- if (!CONST_INT_P (x))
+ if (CONST_INT_P (x))
{
if (mode == Xmode)
- return x;
-
- riscv_emit_unary (ZERO_EXTEND, xmode_reg, x);
- return xmode_reg;
+ emit_move_insn (xmode_reg, x);
+ else
+ {
+ rtx x_reg = gen_reg_rtx (mode);
+ emit_move_insn (x_reg, x);
+ riscv_emit_unary (rcode, xmode_reg, x_reg);
+ }
}
-
- if (mode == Xmode)
- emit_move_insn (xmode_reg, x);
+ else if (mode == Xmode)
+ return x;
else
- {
- rtx reg_x = gen_reg_rtx (mode);
-
- emit_move_insn (reg_x, x);
- riscv_emit_unary (ZERO_EXTEND, xmode_reg, reg_x);
- }
+ riscv_emit_unary (rcode, xmode_reg, x);
return xmode_reg;
}
@@ -12709,8 +12720,8 @@ riscv_expand_usadd (rtx dest, rtx x, rtx y)
machine_mode mode = GET_MODE (dest);
rtx xmode_sum = gen_reg_rtx (Xmode);
rtx xmode_lt = gen_reg_rtx (Xmode);
- rtx xmode_x = riscv_gen_zero_extend_rtx (x, mode);
- rtx xmode_y = riscv_gen_zero_extend_rtx (y, mode);
+ rtx xmode_x = riscv_extend_to_xmode_reg (x, mode, ZERO_EXTEND);
+ rtx xmode_y = riscv_extend_to_xmode_reg (y, mode, ZERO_EXTEND);
rtx xmode_dest = gen_reg_rtx (Xmode);
/* Step-1: sum = x + y */
@@ -12844,8 +12855,8 @@ void
riscv_expand_ussub (rtx dest, rtx x, rtx y)
{
machine_mode mode = GET_MODE (dest);
- rtx xmode_x = riscv_gen_zero_extend_rtx (x, mode);
- rtx xmode_y = riscv_gen_zero_extend_rtx (y, mode);
+ rtx xmode_x = riscv_extend_to_xmode_reg (x, mode, ZERO_EXTEND);
+ rtx xmode_y = riscv_extend_to_xmode_reg (y, mode, ZERO_EXTEND);
rtx xmode_lt = gen_reg_rtx (Xmode);
rtx xmode_minus = gen_reg_rtx (Xmode);
rtx xmode_dest = gen_reg_rtx (Xmode);
--
2.43.0
