Hi,
This patch modifies the combine pattern with a helper -
change_pseudo_and_mask when recog fails. The helper converts a single pseudo to
the pseudo and with a mask if the outer operator is IOR/XOR/PLUS and the inner
operator is ASHIFT/LSHIFTRT/AND. The conversion helps match shift + ior pattern.
Bootstrapped and tested on powerpc64-linux BE and LE with no regressions.
Is this okay for trunk? Any recommendations? Thanks a lot.
ChangeLog
2021-11-30 Haochen Gui <guih...@linux.ibm.com>
gcc/
* combine.c (change_pseudo_and_mask): New.
(recog_for_combine): If recog fails, try again with the pattern
modified by change_pseudo_and_mask.
gcc/testsuite/
* gcc.target/powerpc/20050603-3.c: Modify the dump check conditions.
* gcc.target/powerpc/rlwimi-2.c: Likewise.
patch.diff
diff --git a/gcc/combine.c b/gcc/combine.c
index 03e9a780919..c83c0aceb57 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -11539,6 +11539,42 @@ change_zero_ext (rtx pat)
return changed;
}
+/* When the outer code of set_src is IOR/XOR/PLUS and the inner code is
+ ASHIFT/LSHIFTRT/AND, convert a psuedo to psuedo AND with a mask if its
+ nonzero_bits is less than its mode mask. */
+static bool
+change_pseudo_and_mask (rtx pat)
+{
+ bool changed = false;
+
+ rtx src = SET_SRC (pat);
+ if ((GET_CODE (src) == IOR
+ || GET_CODE (src) == XOR
+ || GET_CODE (src) == PLUS)
+ && (((GET_CODE (XEXP (src, 0)) == ASHIFT
+ || GET_CODE (XEXP (src, 0)) == LSHIFTRT
+ || GET_CODE (XEXP (src, 0)) == AND)
+ && REG_P (XEXP (src, 1)))
+ || ((GET_CODE (XEXP (src, 1)) == ASHIFT
+ || GET_CODE (XEXP (src, 1)) == LSHIFTRT
+ || GET_CODE (XEXP (src, 1)) == AND)
+ && REG_P (XEXP (src, 0)))))
+ {
+ rtx *reg = REG_P (XEXP (src, 0))
+ ? &XEXP (SET_SRC (pat), 0)
+ : &XEXP (SET_SRC (pat), 1);
+ machine_mode mode = GET_MODE (*reg);
+ unsigned HOST_WIDE_INT nonzero = nonzero_bits (*reg, mode);
+ if (nonzero < GET_MODE_MASK (mode))
+ {
+ rtx x = gen_rtx_AND (mode, *reg, GEN_INT (nonzero));
+ SUBST (*reg, x);
+ changed = true;
+ }
+ }
+ return changed;
+}
+
/* Like recog, but we receive the address of a pointer to a new pattern.
We try to match the rtx that the pointer points to.
If that fails, we may try to modify or replace the pattern,
@@ -11586,7 +11622,14 @@ recog_for_combine (rtx *pnewpat, rtx_insn *insn, rtx
*pnotes)
}
}
else
- changed = change_zero_ext (pat);
+ {
+ if (change_pseudo_and_mask (pat))
+ {
+ maybe_swap_commutative_operands (SET_SRC (pat));
+ changed = true;
+ }
+ changed |= change_zero_ext (pat);
+ }
}
else if (GET_CODE (pat) == PARALLEL)
{
diff --git a/gcc/testsuite/gcc.target/powerpc/20050603-3.c
b/gcc/testsuite/gcc.target/powerpc/20050603-3.c
index 4017d34f429..e628be11532 100644
--- a/gcc/testsuite/gcc.target/powerpc/20050603-3.c
+++ b/gcc/testsuite/gcc.target/powerpc/20050603-3.c
@@ -12,7 +12,7 @@ void rotins (unsigned int x)
b.y = (x<<12) | (x>>20);
}
-/* { dg-final { scan-assembler-not {\mrlwinm} } } */
+/* { dg-final { scan-assembler-not {\mrlwinm} { target ilp32 } } } */
/* { dg-final { scan-assembler-not {\mrldic} } } */
/* { dg-final { scan-assembler-not {\mrot[lr]} } } */
/* { dg-final { scan-assembler-not {\ms[lr][wd]} } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c
b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c
index bafa371db73..ffb5f9e450f 100644
--- a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c
@@ -2,14 +2,14 @@
/* { dg-options "-O2" } */
/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 14121 { target ilp32 } }
} */
-/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20217 { target lp64 } } }
*/
+/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 21279 { target lp64 } } }
*/
/* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */
/* { dg-final { scan-assembler-times {(?n)^\s+mr} 643 { target ilp32 } } } */
/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */
/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 7790 { target lp64 } } }
*/
/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1692 { target ilp32 } }
} */
-/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1666 { target lp64 } } }
*/
+/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1692 { target lp64 } } }
*/
/* { dg-final { scan-assembler-times {(?n)^\s+mulli} 5036 } } */
