re PR target/29978 (redundant jumps)

	PR target/29978
	* config/i386/i386.c (ix86_expand_branch): Optimize LE/LEU/GT/GTU
	DImode comparisons against constant with all 1's in the lower word.

	* gcc.target/i386/pr29978.c: New test.

From-SVN: r130938

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b006b495cc32cd7ab450fd52cad1bef1ec35d17a..0875708d2b71e7cc83721d3198fa2c9323ba6a43 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2007-12-14  Jakub Jelinek  <jakub@redhat.com>
+
+       PR target/29978
+       * config/i386/i386.c (ix86_expand_branch): Optimize LE/LEU/GT/GTU
+       DImode comparisons against constant with all 1's in the lower word.
+
 2007-12-14  Uros Bizjak  <ubizjak@gmail.com>
 
        * config/i386/sse.md (sse4_2_pcmpestr): Use reg_not_xmm0_operand

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index fcae07758e0779b2ca7a88abec804371c799e739..95a34969cc6c0aee61b65da7b5b30c674a980f9a 100644 (file)
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -12093,16 +12093,28 @@ ix86_expand_branch (enum rtx_code code, rtx label)
 
        /* Otherwise, if we are doing less-than or greater-or-equal-than,
           op1 is a constant and the low word is zero, then we can just
-          examine the high word.  */
+          examine the high word.  Similarly for low word -1 and
+          less-or-equal-than or greater-than.  */
 
-       if (CONST_INT_P (hi[1]) && lo[1] == const0_rtx)
+       if (CONST_INT_P (hi[1]))
          switch (code)
            {
            case LT: case LTU: case GE: case GEU:
-             ix86_compare_op0 = hi[0];
-             ix86_compare_op1 = hi[1];
-             ix86_expand_branch (code, label);
-             return;
+             if (lo[1] == const0_rtx)
+               {
+                 ix86_compare_op0 = hi[0];
+                 ix86_compare_op1 = hi[1];
+                 ix86_expand_branch (code, label);
+                 return;
+               }
+           case LE: case LEU: case GT: case GTU:
+             if (lo[1] == constm1_rtx)
+               {
+                 ix86_compare_op0 = hi[0];
+                 ix86_compare_op1 = hi[1];
+                 ix86_expand_branch (code, label);
+                 return;
+               }
            default:
              break;
            }

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c6ce8eb2f71ff41fdeb32daa1529e9346aeeaea8..89c022855490f55f1de926acd57722012afcae09 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-12-14  Jakub Jelinek  <jakub@redhat.com>
+
+       PR target/29978
+       * gcc.target/i386/pr29978.c: New test.
+
 2007-12-14  Uros Bizjak  <ubizjak@gmail.com>
 
        * gcc.target/i386/sse-12.c (dg-options): Use -msse4

diff --git a/gcc/testsuite/gcc.target/i386/pr29978.c b/gcc/testsuite/gcc.target/i386/pr29978.c
new file mode 100644 (file)
index 0000000..8c0bf9f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr29978.c
@@ -0,0 +1,16 @@
+/* PR target/29978 */
+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+
+void g ();
+
+void
+f (long long v)
+{
+  if (v > 0xfffffffffLL)
+    g ();
+  g ();
+}
+
+/* Verify there are no redundant jumps jl .L2; jle .L2 */
+/* { dg-final { scan-assembler-not "jl\[^e\]*\\.L" { target ilp32 } } } */