Fix a typo in two_value_replacement function

GCC revision 267634 implemented two_value_replacement function.
However, a typo occurred during the parameter check, which caused
us to miss some optimizations.

The intent of the code might be to check that the input parameters
are const int and their difference is one.  However, when I read
the code, I found that it is wrong to detect whether an input data
plus one is equal to itself.  This could be a typo.

2019-05-07  Li Jia He  <helijia@linux.ibm.com>

	* tree-ssa-phiopt.c (two_value_replacement): Fix a typo in parameter
	detection.
	* gcc.dg/tree-ssa/pr37508.c: Add the no-ssa-phiopt option to skip phi
	optimization.
	* gcc.dg/tree-ssa/pr88676-2.c: New testcase.

From-SVN: r270934

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 41b158cf773557bd954409c5ca7cf01657d6138f..028f992b9f18e10ffcc52fe49834560af4ffe1a8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-07  Li Jia He  <helijia@linux.ibm.com>
+
+       * tree-ssa-phiopt.c (two_value_replacement): Fix a typo in parameter
+       detection.
+
 2019-05-06  Segher Boessenkool  <segher@kernel.crashing.org>
 
        * config/rs6000/rs6000.md (FIRST_ALTIVEC_REGNO, LAST_ALTIVEC_REGNO)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 662b419440b040493501403d4ccc0c69b44ba6e0..28157d3198c54cb7d78e78854204178210478875 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-05-07  Li Jia He  <helijia@linux.ibm.com>
+
+       * gcc.dg/tree-ssa/pr37508.c: Add the no-ssa-phiopt option to skip phi
+       optimization.
+       * gcc.dg/tree-ssa/pr88676-2.c: New testcase.
+
 2019-05-06  Steven G. Kargl  <kargl@gcc.gnu.org>
 
        PR fortran/90290

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr37508.c b/gcc/testsuite/gcc.dg/tree-ssa/pr37508.c
index 2ba09afe4819e622e34798dcbe935a184fe39e77..a6def045de40b725b5e44f2c0c6c6ed97e9c61c2 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr37508.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr37508.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fno-tree-fre -fdump-tree-vrp1" } */
+/* { dg-options "-O2 -fno-ssa-phiopt -fno-tree-fre -fdump-tree-vrp1" } */
 
 struct foo1 {
   int i:1;
@@ -22,7 +22,7 @@ int test2 (struct foo2 *x)
 {
   if (x->i == 0)
     return 1;
-  else if (x->i == -1) /* This test is already folded to false by ccp1.  */
+  else if (x->i == -1) /* This test is already optimized by ccp1 or phiopt1.  */
     return 1;
   return 0;
 }
@@ -31,7 +31,7 @@ int test3 (struct foo1 *x)
 {
   if (x->i == 0)
     return 1;
-  else if (x->i == 1) /* This test is already folded to false by fold.  */
+  else if (x->i == 1) /* This test is already optimized by ccp1 or phiopt1.  */
     return 1;
   return 0;
 }

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr88676-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr88676-2.c
new file mode 100644 (file)
index 0000000..9ad2a50
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr88676-2.c
@@ -0,0 +1,30 @@
+/* PR tree-optimization/88676 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-phiopt1" } */
+/* { dg-final { scan-tree-dump-not " = PHI <" "phiopt1" } } */
+
+struct foo1 {
+  int i:1;
+};
+struct foo2 {
+  unsigned i:1;
+};
+
+int test1 (struct foo1 *x)
+{
+  if (x->i == 0)
+    return 1;
+  else if (x->i == 1)
+    return 1;
+  return 0;
+}
+
+int test2 (struct foo2 *x)
+{
+  if (x->i == 0)
+    return 1;
+  else if (x->i == -1)
+    return 1;
+  return 0;
+}
+

diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 219791ea4ba57c234e96ead69dec3ea00d025ad5..90674a2f3c49a852b208daf032b2934c343c45be 100644 (file)
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -602,7 +602,7 @@ two_value_replacement (basic_block cond_bb, basic_block middle_bb,
       || TREE_CODE (arg1) != INTEGER_CST
       || (tree_int_cst_lt (arg0, arg1)
          ? wi::to_widest (arg0) + 1 != wi::to_widest (arg1)
-         : wi::to_widest (arg1) + 1 != wi::to_widest (arg1)))
+         : wi::to_widest (arg1) + 1 != wi::to_widest (arg0)))
     return false;
 
   if (!empty_block_p (middle_bb))