re PR target/82524 (expensive-optimizations produces wrong results)

	PR target/82524
	* config/i386/i386.md (addqi_ext_1, andqi_ext_1,
	*andqi_ext_1_cc, *<code>qi_ext_1, *xorqi_ext_1_cc): Change
	=Q constraints to +Q and into insn condition add check
	that operands[0] and operands[1] are equal.
	(*addqi_ext_2, *andqi_ext_2, *<code>qi_ext_2): Change
	=Q constraints to +Q and into insn condition add check
	that operands[0] is equal to either operands[1] or operands[2].

	* gcc.c-torture/execute/pr82524.c: New test.

From-SVN: r253710

4 files changed, 80 insertions, 16 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b8346e3..cb9f1a3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,14 @@
 2017-10-13  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/82524
+	* config/i386/i386.md (addqi_ext_1, andqi_ext_1,
+	*andqi_ext_1_cc, *<code>qi_ext_1, *xorqi_ext_1_cc): Change
+	=Q constraints to +Q and into insn condition add check
+	that operands[0] and operands[1] are equal.
+	(*addqi_ext_2, *andqi_ext_2, *<code>qi_ext_2): Change
+	=Q constraints to +Q and into insn condition add check
+	that operands[0] is equal to either operands[1] or operands[2].
+
 	PR target/82498
 	* fold-const.c (fold_binary_loc) <bit_rotate>: Code cleanups,
 	instead of handling MINUS_EXPR twice (once for each argument),
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 2fa982c..3413b90 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -6264,7 +6264,7 @@
    (set_attr "mode" "<MODE>")])
 
 (define_insn "addqi_ext_1"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q,Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -6275,7 +6275,8 @@
 			       (const_int 8)) 0)
 	    (match_operand:QI 2 "general_operand" "QnBc,m")) 0))
    (clobber (reg:CC FLAGS_REG))]
-  ""
+  "/* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   rtx_equal_p (operands[0], operands[1])"
 {
   switch (get_attr_type (insn))
     {
@@ -6300,7 +6301,7 @@
    (set_attr "mode" "QI")])
 
 (define_insn "*addqi_ext_2"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -6314,7 +6315,9 @@
 			       (const_int 8)
 			       (const_int 8)) 0)) 0))
   (clobber (reg:CC FLAGS_REG))]
-  ""
+  "/* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   rtx_equal_p (operands[0], operands[1])
+   || rtx_equal_p (operands[0], operands[2])"
   "add{b}\t{%h2, %h0|%h0, %h2}"
   [(set_attr "type" "alu")
    (set_attr "mode" "QI")])
@@ -8998,7 +9001,7 @@
    (set_attr "mode" "QI")])
 
 (define_insn "andqi_ext_1"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q,Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9009,7 +9012,8 @@
 			       (const_int 8)) 0)
 	    (match_operand:QI 2 "general_operand" "QnBc,m")) 0))
    (clobber (reg:CC FLAGS_REG))]
-  ""
+  "/* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   rtx_equal_p (operands[0], operands[1])"
   "and{b}\t{%2, %h0|%h0, %2}"
   [(set_attr "isa" "*,nox64")
    (set_attr "type" "alu")
@@ -9027,7 +9031,7 @@
 			       (const_int 8)) 0)
 	    (match_operand:QI 2 "general_operand" "QnBc,m"))
 	  (const_int 0)))
-   (set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q,Q")
+   (set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9037,14 +9041,16 @@
 			       (const_int 8)
 			       (const_int 8)) 0)
 	    (match_dup 2)) 0))]
-  "ix86_match_ccmode (insn, CCNOmode)"
+  "ix86_match_ccmode (insn, CCNOmode)
+   /* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   && rtx_equal_p (operands[0], operands[1])"
   "and{b}\t{%2, %h0|%h0, %2}"
   [(set_attr "isa" "*,nox64")
    (set_attr "type" "alu")
    (set_attr "mode" "QI")])
 
 (define_insn "*andqi_ext_2"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9058,7 +9064,9 @@
 			       (const_int 8)
 			       (const_int 8)) 0)) 0))
    (clobber (reg:CC FLAGS_REG))]
-  ""
+  "/* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   rtx_equal_p (operands[0], operands[1])
+   || rtx_equal_p (operands[0], operands[2])"
   "and{b}\t{%h2, %h0|%h0, %h2}"
   [(set_attr "type" "alu")
    (set_attr "mode" "QI")])
@@ -9431,7 +9439,7 @@
    (set_attr "mode" "<MODE>")])
 
 (define_insn "*<code>qi_ext_1"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q,Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9442,14 +9450,16 @@
 			       (const_int 8)) 0)
 	    (match_operand:QI 2 "general_operand" "QnBc,m")) 0))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun)"
+  "(!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun))
+   /* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   && rtx_equal_p (operands[0], operands[1])"
   "<logic>{b}\t{%2, %h0|%h0, %2}"
   [(set_attr "isa" "*,nox64")
    (set_attr "type" "alu")
    (set_attr "mode" "QI")])
 
 (define_insn "*<code>qi_ext_2"
-  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q")
+  [(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9463,7 +9473,10 @@
 			       (const_int 8)
 			       (const_int 8)) 0)) 0))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun)"
+  "(!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun))
+   /* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   && (rtx_equal_p (operands[0], operands[1])
+       || rtx_equal_p (operands[0], operands[2]))"
   "<logic>{b}\t{%h2, %h0|%h0, %h2}"
   [(set_attr "type" "alu")
    (set_attr "mode" "QI")])
@@ -9552,7 +9565,7 @@
 			       (const_int 8)) 0)
 	    (match_operand:QI 2 "general_operand" "QnBc,m"))
 	  (const_int 0)))
-   (set (zero_extract:SI (match_operand 0 "ext_register_operand" "=Q,Q")
+   (set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
 			 (const_int 8)
 			 (const_int 8))
 	(subreg:SI
@@ -9562,7 +9575,9 @@
 			       (const_int 8)
 			       (const_int 8)) 0)
 	  (match_dup 2)) 0))]
-  "ix86_match_ccmode (insn, CCNOmode)"
+  "ix86_match_ccmode (insn, CCNOmode)
+   /* FIXME: without this LRA can't reload this pattern, see PR82524.  */
+   && rtx_equal_p (operands[0], operands[1])"
   "xor{b}\t{%2, %h0|%h0, %2}"
   [(set_attr "isa" "*,nox64")
    (set_attr "type" "alu")
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ff6d743..566864c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2017-10-13  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/82524
+	* gcc.c-torture/execute/pr82524.c: New test.
+
 	PR target/82498
 	* gcc.dg/tree-ssa/pr82498.c: New test.
 
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr82524.c b/gcc/testsuite/gcc.c-torture/execute/pr82524.c
new file mode 100644
index 0000000..07ac4b6
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr82524.c
@@ -0,0 +1,37 @@
+/* PR target/82524 */
+
+struct S { unsigned char b, g, r, a; };
+union U { struct S c; unsigned v; };
+
+static inline unsigned char
+foo (unsigned char a, unsigned char b)
+{
+  return ((a + 1) * b) >> 8;
+}
+
+__attribute__((noinline, noclone)) unsigned
+bar (union U *x, union U *y)
+{
+  union U z;
+  unsigned char v = x->c.a;
+  unsigned char w = foo (y->c.a, 255 - v);
+  z.c.r = foo (x->c.r, v) + foo (y->c.r, w);
+  z.c.g = foo (x->c.g, v) + foo (y->c.g, w);
+  z.c.b = foo (x->c.b, v) + foo (y->c.b, w);
+  z.c.a = 0;
+  return z.v;
+}
+
+int
+main ()
+{
+  union U a, b, c;
+  if ((unsigned char) ~0 != 255 || sizeof (unsigned) != 4)
+    return 0;
+  a.c = (struct S) { 255, 255, 255, 0 };
+  b.c = (struct S) { 255, 255, 255, 255 };
+  c.v = bar (&a, &b);
+  if (c.c.b != 255 || c.c.g != 255 || c.c.r != 255 || c.c.a != 0)
+    __builtin_abort ();
+  return 0;
+}