[AArch64] Don't rely on REG_EQUAL notes to combine SVE BIC

This patch generalises the SVE BIC pattern so that it doesn't
rely on REG_EQUAL notes.  The danger with relying on the notes
is that an optimisation could for example replace the original
(not ...) note with an (unspec ... UNSPEC_MERGE_PTRUE) in which
the predicate is a constant.  That's a legitimate change and
could even be useful in some situations.

The patch also makes the operand order match the SVE operand order in
both the vector and predicate BIC patterns, which makes things easier
for the ACLE.

2019-08-14  Richard Sandiford  <richard.sandiford@arm.com>
	    Kugan Vivekanandarajah  <kugan.vivekanandarajah@linaro.org>

gcc/
	* config/aarch64/aarch64-sve.md (bic<mode>3): Rename to...
	(*bic<SVE_I:mode>3): ...this.  Match the form that an SVE inverse
	actually has, rather than relying on REG_EQUAL notes.
	Make the insn operand order match the SVE operand order.
	(*<nlogical><PRED_ALL:mode>3): Make the insn operand order match
	the SVE operand order.

Co-Authored-By: Kugan Vivekanandarajah <kuganv@linaro.org>
From-SVN: r274416

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ec4aaec093645ab2ff62b5428686719e2adc7461..30663d07eb83016ad7b486ad1786097746886e11 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2019-08-14  Richard Sandiford  <richard.sandiford@arm.com>
+           Kugan Vivekanandarajah  <kugan.vivekanandarajah@linaro.org>
+
+       * config/aarch64/aarch64-sve.md (bic<mode>3): Rename to...
+       (*bic<SVE_I:mode>3): ...this.  Match the form that an SVE inverse
+       actually has, rather than relying on REG_EQUAL notes.
+       Make the insn operand order match the SVE operand order.
+       (*<nlogical><PRED_ALL:mode>3): Make the insn operand order match
+       the SVE operand order.
+
 2019-08-14  Richard Sandiford  <richard.sandiford@arm.com>
 
        * config/aarch64/aarch64.c (aarch64_target_reg): New function.

diff --git a/gcc/config/aarch64/aarch64-sve.md b/gcc/config/aarch64/aarch64-sve.md
index b91d64c726eb179a032d31d10fdda91e56e954c1..7b812b9f5c763b164ea436fcb998e31924301977 100644 (file)
--- a/gcc/config/aarch64/aarch64-sve.md
+++ b/gcc/config/aarch64/aarch64-sve.md
@@ -1779,15 +1779,20 @@
 ;; - BIC
 ;; -------------------------------------------------------------------------
 
-;; REG_EQUAL notes on "not<mode>3" should ensure that we can generate
-;; this pattern even though the NOT instruction itself is predicated.
-(define_insn "bic<mode>3"
+(define_insn_and_rewrite "*bic<mode>3"
   [(set (match_operand:SVE_I 0 "register_operand" "=w")
        (and:SVE_I
-         (not:SVE_I (match_operand:SVE_I 1 "register_operand" "w"))
-         (match_operand:SVE_I 2 "register_operand" "w")))]
+         (unspec:SVE_I
+           [(match_operand 3)
+            (not:SVE_I (match_operand:SVE_I 2 "register_operand" "w"))]
+           UNSPEC_MERGE_PTRUE)
+         (match_operand:SVE_I 1 "register_operand" "w")))]
   "TARGET_SVE"
-  "bic\t%0.d, %2.d, %1.d"
+  "bic\t%0.d, %1.d, %2.d"
+  "&& !CONSTANT_P (operands[3])"
+  {
+    operands[3] = CONSTM1_RTX (<VPRED>mode);
+  }
 )
 
 ;; -------------------------------------------------------------------------
@@ -2451,11 +2456,11 @@
   [(set (match_operand:PRED_ALL 0 "register_operand" "=Upa")
        (and:PRED_ALL
          (NLOGICAL:PRED_ALL
-           (not:PRED_ALL (match_operand:PRED_ALL 2 "register_operand" "Upa"))
-           (match_operand:PRED_ALL 3 "register_operand" "Upa"))
+           (not:PRED_ALL (match_operand:PRED_ALL 3 "register_operand" "Upa"))
+           (match_operand:PRED_ALL 2 "register_operand" "Upa"))
          (match_operand:PRED_ALL 1 "register_operand" "Upa")))]
   "TARGET_SVE"
-  "<nlogical>\t%0.b, %1/z, %3.b, %2.b"
+  "<nlogical>\t%0.b, %1/z, %2.b, %3.b"
 )
 
 ;; -------------------------------------------------------------------------