* match.pd (bit_and (plus/minus (convert @0) (convert @1) mask): New

	simplifier to narrow arithmetic.
	* generic-match-head.c: (types_match, single_use): New functions.
	* gimple-match-head.c: (types_match, single_use): New functions.

	* gcc.dg/tree-ssa/shorten-1.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@222771 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 70930f2302af1695dd220e6927538385b53b1f99..c3b0c3dd0f6392affa734065e5037cbf1dbf40c4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2015-05-04  Jeff Law  <law@redhat.com>
+
+       * match.pd (bit_and (plus/minus (convert @0) (convert @1) mask): New
+       simplifier to narrow arithmetic.
+       * generic-match-head.c: (types_match, single_use): New functions.
+       * gimple-match-head.c: (types_match, single_use): New functions.
+
 2015-05-04  Andreas Tobler  <andreast@gcc.gnu.org>
 
        * config/arm/arm.c: Restore bootstrap.

diff --git a/gcc/generic-match-head.c b/gcc/generic-match-head.c
index daa56aa370ec6c93024e2c541aa10a6c33e2c597..303b23759a13fd4310896c4d21c7ad8216a1d756 100644 (file)
--- a/gcc/generic-match-head.c
+++ b/gcc/generic-match-head.c
@@ -70,4 +70,20 @@ along with GCC; see the file COPYING3.  If not see
 #include "dumpfile.h"
 #include "generic-match.h"
 
+/* Routine to determine if the types T1 and T2 are effectively
+   the same for GENERIC.  */
 
+inline bool
+types_match (tree t1, tree t2)
+{
+  return TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2);
+}
+
+/* Return if T has a single use.  For GENERIC, we assume this is
+   always true.  */
+
+inline bool
+single_use (tree t)
+{
+  return true;
+}

diff --git a/gcc/gimple-match-head.c b/gcc/gimple-match-head.c
index c7b2f957baca4bd05c25988938d126d817404fbe..dc13218b2bf2f7034c88dfb2989d6f86e79d4a6b 100644 (file)
--- a/gcc/gimple-match-head.c
+++ b/gcc/gimple-match-head.c
@@ -861,3 +861,21 @@ do_valueize (tree (*valueize)(tree), tree op)
   return op;
 }
 
+/* Routine to determine if the types T1 and T2 are effectively
+   the same for GIMPLE.  */
+
+inline bool
+types_match (tree t1, tree t2)
+{
+  return types_compatible_p (t1, t2);
+}
+
+/* Return if T has a single use.  For GIMPLE, we also allow any
+   non-SSA_NAME (ie constants) and zero uses to cope with uses
+   that aren't linked up yet.  */
+
+inline bool
+single_use (tree t)
+{
+  return TREE_CODE (t) != SSA_NAME || has_zero_uses (t) || has_single_use (t);
+}

diff --git a/gcc/match.pd b/gcc/match.pd
index 87ecaf10140780243c58b90d0909d4b6c55799c9..51a950acaa960c49afb17db612856ca61f6926eb 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -289,8 +289,7 @@ along with GCC; see the file COPYING3.  If not see
   (if (((TREE_CODE (@1) == INTEGER_CST
         && INTEGRAL_TYPE_P (TREE_TYPE (@0))
         && int_fits_type_p (@1, TREE_TYPE (@0)))
-       || (GIMPLE && types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1)))
-       || (GENERIC && TREE_TYPE (@0) == TREE_TYPE (@1)))
+       || types_match (TREE_TYPE (@0), TREE_TYPE (@1)))
        /* ???  This transform conflicts with fold-const.c doing
          Convert (T)(x & c) into (T)x & (T)c, if c is an integer
          constants (if x has signed type, the sign bit cannot be set
@@ -949,8 +948,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Unordered tests if either argument is a NaN.  */
 (simplify
  (bit_ior (unordered @0 @0) (unordered @1 @1))
- (if ((GIMPLE && types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1)))
-      || (GENERIC && TREE_TYPE (@0) == TREE_TYPE (@1)))
+ (if (types_match (TREE_TYPE (@0), TREE_TYPE (@1)))
   (unordered @0 @1)))
 (simplify
  (bit_ior:c (unordered @0 @0) (unordered:c@2 @0 @1))
@@ -1054,7 +1052,7 @@ along with GCC; see the file COPYING3.  If not see
    operation and convert the result to the desired type.  */
 (for op (plus minus)
   (simplify
-    (convert (op (convert@2 @0) (convert@3 @1)))
+    (convert (op@4 (convert@2 @0) (convert@3 @1)))
     (if (INTEGRAL_TYPE_P (type)
         /* We check for type compatibility between @0 and @1 below,
            so there's no need to check that @1/@3 are integral types.  */
@@ -1070,15 +1068,45 @@ along with GCC; see the file COPYING3.  If not see
         && TYPE_PRECISION (type) == GET_MODE_PRECISION (TYPE_MODE (type))
         /* The inner conversion must be a widening conversion.  */
         && TYPE_PRECISION (TREE_TYPE (@2)) > TYPE_PRECISION (TREE_TYPE (@0))
-        && ((GENERIC 
-             && (TYPE_MAIN_VARIANT (TREE_TYPE (@0))
-                 == TYPE_MAIN_VARIANT (TREE_TYPE (@1)))
-             && (TYPE_MAIN_VARIANT (TREE_TYPE (@0))
-                 == TYPE_MAIN_VARIANT (type)))
-            || (GIMPLE
-                && types_compatible_p (TREE_TYPE (@0), TREE_TYPE (@1))
-                && types_compatible_p (TREE_TYPE (@0), type))))
+        && types_match (TREE_TYPE (@0), TREE_TYPE (@1))
+        && types_match (TREE_TYPE (@0), type)
+        && single_use (@4))
       (if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
        (convert (op @0 @1)))
       (with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
        (convert (op (convert:utype @0) (convert:utype @1)))))))
+
+/* This is another case of narrowing, specifically when there's an outer
+   BIT_AND_EXPR which masks off bits outside the type of the innermost
+   operands.   Like the previous case we have to convert the operands
+   to unsigned types to avoid introducing undefined behaviour for the
+   arithmetic operation.  */
+(for op (minus plus)
+  (simplify
+    (bit_and (op@5 (convert@2 @0) (convert@3 @1)) INTEGER_CST@4)
+    (if (INTEGRAL_TYPE_P (type)
+        /* We check for type compatibility between @0 and @1 below,
+           so there's no need to check that @1/@3 are integral types.  */
+        && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+        && INTEGRAL_TYPE_P (TREE_TYPE (@2))
+        /* The precision of the type of each operand must match the
+           precision of the mode of each operand, similarly for the
+           result.  */
+        && (TYPE_PRECISION (TREE_TYPE (@0))
+            == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (@0))))
+        && (TYPE_PRECISION (TREE_TYPE (@1))
+            == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (@1))))
+        && TYPE_PRECISION (type) == GET_MODE_PRECISION (TYPE_MODE (type))
+        /* The inner conversion must be a widening conversion.  */
+        && TYPE_PRECISION (TREE_TYPE (@2)) > TYPE_PRECISION (TREE_TYPE (@0))
+        && types_match (TREE_TYPE (@0), TREE_TYPE (@1))
+        && (tree_int_cst_min_precision (@4, UNSIGNED)
+            <= TYPE_PRECISION (TREE_TYPE (@0)))
+        && single_use (@5))
+      (if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
+       (with { tree ntype = TREE_TYPE (@0); }
+         (convert (bit_and (op @0 @1) (convert:ntype @4)))))
+      (with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
+       (convert (bit_and (op (convert:utype @0) (convert:utype @1))
+                         (convert:utype @4)))))))
+

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cb7bc61bb1228f791b22cbf47c1351fce304b06c..0658ea0cc3f3272e97a052001f0969233f86bd82 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-05-04  Jeff Law  <law@redhat.com>
+
+       * gcc.dg/tree-ssa/shorten-1.c: New test.
+
 2015-05-04  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
        PR fortran/44735

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/shorten-1.c b/gcc/testsuite/gcc.dg/tree-ssa/shorten-1.c
new file mode 100644 (file)
index 0000000..c9015c5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/shorten-1.c
@@ -0,0 +1,79 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+extern const unsigned char mode_ibit[];
+extern const unsigned char mode_fbit[];
+extern const signed char smode_ibit[];
+extern const signed char smode_fbit[];
+
+/* We use bit-and rather than modulo to ensure we're actually
+   testing the desired match.pd pattern.  */
+unsigned char
+muufubar (int indx)
+{
+  int ret = (mode_fbit [indx] - mode_ibit [indx]) & 3;
+  return ret;
+}
+
+signed char
+msufubar (int indx)
+{
+  int ret = (mode_fbit [indx] - mode_ibit [indx]) & 3;
+  return ret;
+}
+
+unsigned char
+musfubar (int indx)
+{
+  int ret = (smode_fbit [indx] - smode_ibit [indx]) & 3;
+  return ret;
+}
+
+signed char
+mssfubar (int indx)
+{
+  int ret = (smode_fbit [indx] - smode_ibit [indx]) & 3;
+  return ret;
+}
+
+
+unsigned char
+puufubar (int indx)
+{
+  int ret = (mode_fbit [indx] + mode_ibit [indx]) & 3;
+  return ret;
+}
+
+signed char
+psufubar (int indx)
+{
+  int ret = (mode_fbit [indx] + mode_ibit [indx]) & 3;
+  return ret;
+}
+
+unsigned char
+pusfubar (int indx)
+{
+  int ret = (smode_fbit [indx] + smode_ibit [indx]) & 3;
+  return ret;
+}
+
+signed char
+pssfubar (int indx)
+{
+  int ret = (smode_fbit [indx] + smode_ibit [indx]) & 3;
+  return ret;
+}
+
+/* The shortening patterns in match.pd should arrange to do the
+   arithmetic in char modes and thus any casts to ints should
+   have been removed.  */
+/* { dg-final {scan-tree-dump-not "\\(int\\)" "optimized"} } */
+
+/* We should have casted 4 operands from signed to unsigned char types.  */
+/* { dg-final {scan-tree-dump-times "\\(unsigned char\\)" 8 "optimized" } } */
+
+/* And two return values should have been casted from unsigned char to
+   a normal char.  */
+/* { dg-final {scan-tree-dump-times "\\(signed char\\)" 4 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */