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[committed] PR target/67329: gcc.dg/tree-ssa/ssa-dom-cse-2.c fails on -march=pentium or -march=iamcu

Message ID 20150824152549.GA19522@intel.com
State New
Headers show

Commit Message

H.J. Lu Aug. 24, 2015, 3:25 p.m. UTC 
This patch updates MOVE_RATIO cost for IA MCU from 6 to 9 so that we
can unroll the loop completely for DOM with -mtune=iamcu.

gcc/

	PR target/67329
	* config/i386/i386.c (iamcu_cost): Set MOVE_RATIO cost to 9.

gcc/testsuite/

	PR target/67329
	* gcc.target/i386/pr67329.c: New test.
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Patch

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index a463239..4f79bc0 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -436,7 +436,7 @@  struct processor_costs iamcu_cost = {
   COSTS_N_INSNS (3),			/* cost of movsx */
   COSTS_N_INSNS (2),			/* cost of movzx */
   8,					/* "large" insn */
-  6,					/* MOVE_RATIO */
+  9,					/* MOVE_RATIO */
   6,				     /* cost for loading QImode using movzbl */
   {2, 4, 2},				/* cost of loading integer registers
 					   in QImode, HImode and SImode.
diff --git a/gcc/testsuite/gcc.target/i386/pr67329.c b/gcc/testsuite/gcc.target/i386/pr67329.c
new file mode 100644
index 0000000..a29dd5b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67329.c
@@ -0,0 +1,20 @@ 
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O3 -fno-tree-fre -fno-tree-pre -fdump-tree-optimized -mtune=iamcu" } */
+
+int
+foo ()
+{
+  const int a[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };
+  int i, sum;
+
+  sum = 0;
+  for (i = 0; i < sizeof (a) / sizeof (*a); i++)
+    sum += a[i];
+
+  return sum;
+}
+
+/* After late unrolling the above loop completely DOM should be
+   able to optimize this to return 28.  */
+
+/* { dg-final { scan-tree-dump "return 28;" "optimized" } } */