===================================================================
@@ -2809,10 +2809,9 @@ dimode_scalar_to_vector_candidate_p (rtx_insn *ins
{
case ASHIFT:
case LSHIFTRT:
- /* Consider only non-variable shifts narrower
- than general register width. */
- if (!(CONST_INT_P (XEXP (src, 1))
- && IN_RANGE (INTVAL (XEXP (src, 1)), 0, 31)))
+ /* FIXME: consider also variable shifts. */
+ if (!CONST_INT_P (XEXP (src, 1))
+ || !IN_RANGE (INTVAL (XEXP (src, 1)), 0, 63))
return false;
break;
@@ -3409,6 +3408,9 @@ dimode_scalar_chain::compute_convert_gain ()
gain += ix86_cost->add;
if (CONST_INT_P (XEXP (src, 0)))
gain -= vector_const_cost (XEXP (src, 0));
+ if (CONST_INT_P (XEXP (src, 1))
+ && INTVAL (XEXP (src, 1)) >= 32)
+ gain -= COSTS_N_INSNS (1);
}
else if (GET_CODE (src) == PLUS
|| GET_CODE (src) == MINUS
===================================================================
@@ -0,0 +1,17 @@
+/* PR target/pr70799 */
+/* { dg-do compile { target { ia32 } } } */
+/* { dg-options "-O2 -march=slm -fno-split-wide-types -mno-stackrealign" } */
+/* { dg-final { scan-assembler "psllq" } } */
+/* { dg-final { scan-assembler "psrlq" } } */
+
+unsigned long long a, b, c;
+
+void test1 (void)
+{
+ a = (b << 55) | c;
+}
+
+void test2 (void)
+{
+ a = (b >> 55) | c;
+}
Hello! Attached patch improves cost function for STV transform of shifts with constant count operand. The new cost function reduces the gain by COST_N_INSN(1) for shifts larger than or equal to 32. 2016-12-11 Uros Bizjak <ubizjak@gmail.com> PR target/70799 * config/i386/i386.c (dimode_scalar_to_vector_candidate_p) <case ASHIFT, case LSHIFTRT>: Consider all constant shifts. Add FIXME comment. (dimode_scalar_chain::compute_convert_gain): Reduce gain for constant shifts larger or equal than 32. testsuite/ChangeLog: 2016-12-11 Uros Bizjak <ubizjak@gmail.com> PR target/70799 * gcc.target/i386/pr70799-3.c: New test. Bootstrapped and regression tested on x86_64-linux-gnu, committed to mainline SVN. Uros.