This patch provides an improved rtx_costs target hook on xstormy16.
The current implementation has the unfortunate property that it claims
that zero_extendhisi2 is very cheap, even though the machine description
doesn't provide that instruction/pattern. Doh! Rewriting the
xstormy16_rtx_costs function has additional benefits, including
making more use of the (short) "mul" instruction when optimizing
for size with -Os.
This patch has been tested by building a cross-compiler to xstormy-elf
on x86_64-pc-linux-gnu, and confirming that the new test case passes
with "make -k check-gcc". Many thanks to Jeff Law for additional
testing. Ok for mainline?
2023-04-22 Roger Sayle <ro...@nextmovesoftware.com>
gcc/ChangeLog
* config/stormy16/stormy16.cc (xstormy16_rtx_costs): Rewrite to
provide reasonable values for common arithmetic operations and
immediate operands (in several machine modes).
gcc/testsuite/ChangeLog
* gcc.target/xstormy16/mulhi.c: New test case.
Roger
--
diff --git a/gcc/config/stormy16/stormy16.cc b/gcc/config/stormy16/stormy16.cc
index 1ed619a..e6d6fbd 100644
--- a/gcc/config/stormy16/stormy16.cc
+++ b/gcc/config/stormy16/stormy16.cc
@@ -72,19 +72,23 @@ static GTY(()) section *bss100_section;
scanned. In either case, *TOTAL contains the cost result. */
static bool
-xstormy16_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
+xstormy16_rtx_costs (rtx x, machine_mode mode,
int outer_code ATTRIBUTE_UNUSED,
- int opno ATTRIBUTE_UNUSED, int *total,
- bool speed ATTRIBUTE_UNUSED)
+ int opno ATTRIBUTE_UNUSED, int *total, bool speed_p)
{
- int code = GET_CODE (x);
+ rtx_code code = GET_CODE (x);
switch (code)
{
case CONST_INT:
- if (INTVAL (x) < 16 && INTVAL (x) >= 0)
- *total = COSTS_N_INSNS (1) / 2;
- else if (INTVAL (x) < 256 && INTVAL (x) >= 0)
+ if (mode == SImode)
+ {
+ HOST_WIDE_INT lo_word = INTVAL (x) & 0xffff;
+ HOST_WIDE_INT hi_word = INTVAL (x) >> 16;
+ *total = COSTS_N_INSNS (IN_RANGE (lo_word, 0, 255) ? 1 : 2);
+ *total += COSTS_N_INSNS (IN_RANGE (hi_word, 0, 255) ? 1 : 2);
+ }
+ else if (mode == QImode || IN_RANGE(INTVAL (x), 0, 255))
*total = COSTS_N_INSNS (1);
else
*total = COSTS_N_INSNS (2);
@@ -97,12 +101,152 @@ xstormy16_rtx_costs (rtx x, machine_mode mode
ATTRIBUTE_UNUSED,
*total = COSTS_N_INSNS (2);
return true;
+ case PLUS:
+ case MINUS:
+ if (mode == SImode)
+ {
+ if (CONST_INT_P (XEXP (x, 1)))
+ {
+ HOST_WIDE_INT lo_word = INTVAL (XEXP (x, 1)) & 0xffff;
+ HOST_WIDE_INT hi_word = INTVAL (XEXP (x, 1)) >> 16;
+ if (IN_RANGE (lo_word, 0, 16))
+ *total = COSTS_N_INSNS (1);
+ else
+ *total = COSTS_N_INSNS (2);
+ if (IN_RANGE (hi_word, 0, 16))
+ *total += COSTS_N_INSNS (1);
+ else
+ *total += COSTS_N_INSNS (2);
+ }
+ else
+ {
+ *total = COSTS_N_INSNS (2);
+ *total += rtx_cost (XEXP (x, 1), mode, code, 0, speed_p);
+ }
+ *total += rtx_cost (XEXP (x, 0), mode, code, 0, speed_p);
+ return true;
+ }
+ else
+ {
+ if (CONST_INT_P (XEXP (x, 1)))
+ {
+ if (IN_RANGE (INTVAL (XEXP (x, 1)), 0, 16))
+ *total = COSTS_N_INSNS (1);
+ else
+ *total = COSTS_N_INSNS (2);
+ }
+ else
+ {
+ *total = COSTS_N_INSNS (1);
+ *total += rtx_cost (XEXP (x, 1), mode, code, 0, speed_p);
+ }
+ *total += rtx_cost (XEXP (x, 0), mode, code, 0, speed_p);
+ return true;
+ }
+ return false;
+
case MULT:
- *total = COSTS_N_INSNS (35 + 6);
- return true;
+ if (mode == QImode)
+ *total = COSTS_N_INSNS (speed_p ? 18 + 5 : 6);
+ else if (mode == SImode)
+ *total = COSTS_N_INSNS (speed_p ? 3 * 18 + 14 : 17);
+ else
+ *total = COSTS_N_INSNS (speed_p ? 18 + 3 : 4);
+ return false;
+
case DIV:
- *total = COSTS_N_INSNS (51 - 6);
- return true;
+ case MOD:
+ if (mode == QImode)
+ *total = COSTS_N_INSNS (speed_p ? 19 + 6 : 7);
+ else if (mode == SImode)
+ *total = COSTS_N_INSNS (speed_p ? 100 : 7);
+ else
+ *total = COSTS_N_INSNS (speed_p ? 19 + 3 : 4);
+ return false;
+
+ case UDIV:
+ case UMOD:
+ if (mode == QImode)
+ *total = COSTS_N_INSNS (speed_p ? 18 + 7 : 8);
+ else if (mode == SImode)
+ *total = COSTS_N_INSNS (speed_p ? 100 : 7);
+ else
+ *total = COSTS_N_INSNS (speed_p ? 18 + 3 : 4);
+ return false;
+
+ case ASHIFT:
+ case ASHIFTRT:
+ case LSHIFTRT:
+ if (REG_P (XEXP (x, 0))
+ && CONST_INT_P (XEXP (x, 1)))
+ {
+ if (mode == HImode)
+ {
+ /* asr/shl/shr. */
+ *total = COSTS_N_INSNS (1);
+ return true;
+ }
+ else if (mode == QImode)
+ {
+ /* (shl+shr)+shr. */
+ *total = COSTS_N_INSNS (3);
+ return true;
+ }
+ else if (mode == SImode)
+ {
+ if (IN_RANGE (INTVAL (XEXP (x, 1)), 16, 31))
+ *total = COSTS_N_INSNS (3);
+ else
+ *total = COSTS_N_INSNS (5);
+ return true;
+ }
+ }
+ return false;
+
+ case ZERO_EXTEND:
+ if (mode == HImode)
+ {
+ if (GET_MODE (XEXP (x, 0)) == QImode)
+ /* shl+shr. */
+ *total = COSTS_N_INSNS (2);
+ }
+ else if (mode == SImode)
+ {
+ if (GET_MODE (XEXP (x, 0)) == HImode)
+ /* mov+mov. */
+ *total = COSTS_N_INSNS (2);
+ else if (GET_MODE (XEXP (x, 0)) == QImode)
+ /* mov+shl+shr+mov. */
+ *total = COSTS_N_INSNS (4);
+ }
+ return false;
+
+ case SIGN_EXTEND:
+ if (mode == HImode)
+ {
+ if (GET_MODE (XEXP (x, 0)) == QImode)
+ /* cbw. */
+ *total = COSTS_N_INSNS (1);
+ }
+ else if (mode == SImode)
+ {
+ if (GET_MODE (XEXP (x, 0)) == HImode)
+ /* mov+asr. */
+ *total = COSTS_N_INSNS (2);
+ else if (GET_MODE (XEXP (x, 0)) == QImode)
+ /* mov+shl+shr+mov. */
+ *total = COSTS_N_INSNS (3);
+ }
+ return false;
+
+ case SET:
+ if (REG_P (XEXP (x, 0)))
+ {
+ if (!REG_P (XEXP (x, 1)))
+ *total = rtx_cost (XEXP (x, 1), mode, SET, 1, speed_p);
+ return true;
+ }
+ return false;
default:
return false;
diff --git a/gcc/testsuite/gcc.target/xstormy16/mulhi.c
b/gcc/testsuite/gcc.target/xstormy16/mulhi.c
new file mode 100644
index 0000000..885f145
--- /dev/null
+++ b/gcc/testsuite/gcc.target/xstormy16/mulhi.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+unsigned short foo(unsigned short x)
+{
+ return x*91;
+}
+
+/* { dg-final { scan-assembler "mul" } } */
