ii386: Generate QImode binary ops with high-part input register [PR108831]

Following testcase:

--cut here--
struct S
{
  unsigned char pad1;
  unsigned char val;
  unsigned short pad2;
};

unsigned char
test_add (unsigned char a, struct S b)
{
  a += b.val;

  return a;
}
--cut here--

should be compiled to something like:

        addb %dh, %al

but is currently compiled to:

        movzbl  %dh, %edx
        addl    %edx, %eax

The patch implements insn patterns that model QImode binary ops with
high-part QImode input register.  These ops can not be encoded with
REX prefix, so only Q registers and constant memory output operands
are allowed on x86_64 targets.

2023-02-17  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	PR target/108831
	* config/i386/predicates.md
	(nonimm_x64constmem_operand): New predicate.
	* config/i386/i386.md (*addqi_ext<mode>_0): New insn pattern.
	(*subqi_ext<mode>_0): Ditto.
	(*andqi_ext<mode>_0): Ditto.
	(*<any_or:code>qi_ext<mode>_0): Ditto.

gcc/testsuite/ChangeLog:

	PR target/108831
	* gcc.target/i386/pr108831-1.c: New test.
	* gcc.target/i386/pr108831-2.c: Ditto.

4 files changed, 189 insertions, 0 deletions

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 198f06e..55042e7 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -6641,6 +6641,22 @@
 	(const_string "*")))
    (set_attr "mode" "<MODE>")])
 
+(define_insn "*addqi_ext<mode>_0"
+  [(set (match_operand:QI 0 "nonimm_x64constmem_operand" "=QBc,m")
+	(plus:QI
+	  (subreg:QI
+	    (zero_extract:SWI248
+	      (match_operand 2 "int248_register_operand" "Q,Q")
+	      (const_int 8)
+	      (const_int 8)) 0)
+	  (match_operand:QI 1 "nonimm_x64constmem_operand" "0,0")))
+   (clobber (reg:CC FLAGS_REG))]
+  ""
+  "add{b}\t{%h2, %0|%0, %h2}"
+  [(set_attr "isa" "*,nox64")
+   (set_attr "type" "alu")
+   (set_attr "mode" "QI")])
+
 (define_expand "addqi_ext_1"
   [(parallel
      [(set (zero_extract:HI (match_operand:HI 0 "register_operand")
@@ -7265,6 +7281,22 @@
   [(set_attr "type" "alu")
    (set_attr "mode" "SI")])
 
+(define_insn "*subqi_ext<mode>_0"
+  [(set (match_operand:QI 0 "nonimm_x64constmem_operand" "=QBc,m")
+	(minus:QI
+	  (match_operand:QI 1 "nonimm_x64constmem_operand" "0,0")
+	  (subreg:QI
+	    (zero_extract:SWI248
+	      (match_operand 2 "int248_register_operand" "Q,Q")
+	      (const_int 8)
+	      (const_int 8)) 0)))
+   (clobber (reg:CC FLAGS_REG))]
+  ""
+  "sub{b}\t{%h2, %0|%0, %h2}"
+  [(set_attr "isa" "*,nox64")
+   (set_attr "type" "alu")
+   (set_attr "mode" "QI")])
+
 (define_insn "*subqi_ext<mode>_2"
   [(set (zero_extract:SWI248
 	  (match_operand 0 "int248_register_operand" "+Q")
@@ -10528,6 +10560,22 @@
   [(set_attr "type" "alu")
    (set_attr "mode" "<MODE>")])
 
+(define_insn "*andqi_ext<mode>_0"
+  [(set (match_operand:QI 0 "nonimm_x64constmem_operand" "=QBc,m")
+	(and:QI
+	  (subreg:QI
+	    (zero_extract:SWI248
+	      (match_operand 2 "int248_register_operand" "Q,Q")
+	      (const_int 8)
+	      (const_int 8)) 0)
+	  (match_operand:QI 1 "nonimm_x64constmem_operand" "0,0")))
+   (clobber (reg:CC FLAGS_REG))]
+  ""
+  "and{b}\t{%h2, %0|%0, %h2}"
+  [(set_attr "isa" "*,nox64")
+   (set_attr "type" "alu")
+   (set_attr "mode" "QI")])
+
 (define_expand "andqi_ext_1"
   [(parallel
      [(set (zero_extract:HI (match_operand:HI 0 "register_operand")
@@ -11269,6 +11317,22 @@
   [(set_attr "type" "alu")
    (set_attr "mode" "<MODE>")])
 
+(define_insn "*<code>qi_ext<mode>_0"
+  [(set (match_operand:QI 0 "nonimm_x64constmem_operand" "=QBc,m")
+	(any_or:QI
+	  (subreg:QI
+	    (zero_extract:SWI248
+	      (match_operand 2 "int248_register_operand" "Q,Q")
+	      (const_int 8)
+	      (const_int 8)) 0)
+	  (match_operand:QI 1 "nonimm_x64constmem_operand" "0,0")))
+   (clobber (reg:CC FLAGS_REG))]
+  ""
+  "<logic>{b}\t{%h2, %0|%0, %h2}"
+  [(set_attr "isa" "*,nox64")
+   (set_attr "type" "alu")
+   (set_attr "mode" "QI")])
+
 (define_insn "*<code>qi_ext<mode>_1"
   [(set (zero_extract:SWI248
 	  (match_operand 0 "int248_register_operand" "+Q,Q")
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 2f079a6..7b3db0c 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -109,6 +109,13 @@
 	    (match_test "GET_MODE (op) == HImode")
 	    (match_test "GET_MODE (op) == QImode"))))
 
+;; Match nonimmediate operand, but exclude non-constant addresses for x86_64.
+(define_predicate "nonimm_x64constmem_operand"
+  (ior (match_operand 0 "register_operand")
+       (and (match_operand 0 "memory_operand")
+	    (ior (not (match_test "TARGET_64BIT"))
+		 (match_test "constant_address_p (XEXP (op, 0))")))))
+
 ;; Match register operands, but include memory operands for TARGET_SSE_MATH.
 (define_predicate "register_ssemem_operand"
   (if_then_else
diff --git a/gcc/testsuite/gcc.target/i386/pr108831-1.c b/gcc/testsuite/gcc.target/i386/pr108831-1.c
new file mode 100644
index 0000000..3499b18
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr108831-1.c
@@ -0,0 +1,63 @@
+/* PR target/108831 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -masm=att" } */
+/* { dg-additional-options "-mregparm=3" { target ia32 } } */
+/* { dg-final { scan-assembler-not "movzbl" } } */
+/* { dg-final { scan-assembler-not "movb" } } */
+
+struct S
+{
+  unsigned char pad1;
+  unsigned char val;
+  unsigned short pad2;
+};
+
+unsigned char
+test_and (unsigned char a, struct S b)
+{
+  a &= b.val;
+
+  return a;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]andb" } } */
+
+unsigned char
+test_or (unsigned char a, struct S b)
+{
+  a |= b.val;
+
+  return a;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]orb" } } */
+
+unsigned char
+test_xor (unsigned char a, struct S b)
+{
+  a ^= b.val;
+
+  return a;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]xorb" } } */
+
+unsigned char
+test_add (unsigned char a, struct S b)
+{
+  a += b.val;
+
+  return a;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]addb" } } */
+
+unsigned char
+test_sub (unsigned char a, struct S b)
+{
+  a -= b.val;
+
+  return a;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]subb" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr108831-2.c b/gcc/testsuite/gcc.target/i386/pr108831-2.c
new file mode 100644
index 0000000..a415391
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr108831-2.c
@@ -0,0 +1,55 @@
+/* PR target/108831 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -masm=att" } */
+/* { dg-additional-options "-mregparm=3" { target ia32 } } */
+/* { dg-final { scan-assembler-not "movzbl" } } */
+/* { dg-final { scan-assembler-not "movb" } } */
+
+struct S
+{
+  unsigned char pad1;
+  unsigned char val;
+  unsigned short pad2;
+};
+
+unsigned char a;
+
+void
+test_and (struct S b)
+{
+  a &= b.val;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]andb" } } */
+
+void
+test_or (struct S b)
+{
+  a |= b.val;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]orb" } } */
+
+void
+test_xor (struct S b)
+{
+  a ^= b.val;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]xorb" } } */
+
+void
+test_add (struct S b)
+{
+  a += b.val;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]addb" } } */
+
+void
+test_sub (struct S b)
+{
+  a -= b.val;
+}
+
+/* { dg-final { scan-assembler "\[ \t\]subb" } } */