Patchwork [ARM] Prevent inappropriate attempt to conditionalize inline synchronization sequences.

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Submitter Marcus Shawcroft
Date Sept. 13, 2010, 11:06 a.m.
Message ID <000c01cb5333$c1ca76e0$455f64a0$@shawcroft@arm.com>
Download mbox | patch
Permalink /patch/64581/
State New
Headers show

Comments

Marcus Shawcroft - Sept. 13, 2010, 11:06 a.m.
All but one of the define_insn patterns for inline synchronization builtins
have the conds attribute set to nocond. This incorrectly allows the
instruction to be conditionalized.

This patch adds a test case and fixes the issue.

/Marcus
2010-09-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>

        * config/arm/arm.md: (define_attr "conds"): Update comment.
	* config/arm/sync.md (arm_sync_compare_and_swapsi): Change 
          conds attribute to clob.
          (arm_sync_compare_and_swapsi): Likewise.
	  (arm_sync_compare_and_swap<mode>): Likewise.
	  (arm_sync_lock_test_and_setsi): Likewise.
	  (arm_sync_lock_test_and_set<mode>): Likewise.
	  (arm_sync_new_<sync_optab>si): Likewise.
	  (arm_sync_new_nandsi): Likewise.
	  (arm_sync_new_<sync_optab><mode>): Likewise.
	  (arm_sync_new_nand<mode>): Likewise.
	  (arm_sync_old_<sync_optab>si): Likewise.
	  (arm_sync_old_nandsi): Likewise.
	  (arm_sync_old_<sync_optab><mode>): Likewise.
	  (arm_sync_old_nand<mode>): Likewise.

2010-09-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>

	* gcc.target/arm/sync-1.c: New.
Richard Earnshaw - Sept. 13, 2010, 2:18 p.m.
On Mon, 2010-09-13 at 12:06 +0100, Marcus Shawcroft wrote:
> All but one of the define_insn patterns for inline synchronization builtins
> have the conds attribute set to nocond. This incorrectly allows the
> instruction to be conditionalized.
> 
> This patch adds a test case and fixes the issue.
> 
> /Marcus

2010-09-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>

        * config/arm/arm.md: (define_attr "conds"): Update comment.
        * config/arm/sync.md (arm_sync_compare_and_swapsi): Change 
          conds attribute to clob.
          (arm_sync_compare_and_swapsi): Likewise.
          (arm_sync_compare_and_swap<mode>): Likewise.
          (arm_sync_lock_test_and_setsi): Likewise.
          (arm_sync_lock_test_and_set<mode>): Likewise.
          (arm_sync_new_<sync_optab>si): Likewise.
          (arm_sync_new_nandsi): Likewise.
          (arm_sync_new_<sync_optab><mode>): Likewise.
          (arm_sync_new_nand<mode>): Likewise.
          (arm_sync_old_<sync_optab>si): Likewise.
          (arm_sync_old_nandsi): Likewise.
          (arm_sync_old_<sync_optab><mode>): Likewise.
          (arm_sync_old_nand<mode>): Likewise.

2010-09-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>

        * gcc.target/arm/sync-1.c: New.

OK.

R.

Patch

diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 9d7310b..6e64d38 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -419,10 +419,11 @@ 
 ; CLOB means that the condition codes are altered in an undefined manner, if
 ;   they are altered at all
 ;
-; UNCONDITIONAL means the instions can not be conditionally executed.
+; UNCONDITIONAL means the instruction can not be conditionally executed and
+;   that the instruction does not use or alter the condition codes.
 ;
-; NOCOND means that the condition codes are neither altered nor affect the
-;   output of this insn
+; NOCOND means that the instruction does not use or alter the condition
+;   codes but can be converted into a conditionally exectuted instruction.
 
 (define_attr "conds" "use,set,clob,unconditional,nocond"
 	(if_then_else
diff --git a/gcc/config/arm/sync.md b/gcc/config/arm/sync.md
index f942d1f..4c4b4fa 100644
--- a/gcc/config/arm/sync.md
+++ b/gcc/config/arm/sync.md
@@ -300,7 +300,7 @@ 
    (set_attr "sync_new_value"       "3")
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "4")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_compare_and_swap<mode>"
@@ -327,7 +327,7 @@ 
    (set_attr "sync_new_value"       "3")
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "4")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_lock_test_and_setsi"
@@ -348,7 +348,7 @@ 
    (set_attr "sync_new_value"       "2")
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_lock_test_and_set<mode>"
@@ -369,7 +369,7 @@ 
    (set_attr "sync_new_value"       "2")
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_new_<sync_optab>si"
@@ -394,7 +394,7 @@ 
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
    (set_attr "sync_op"              "<sync_optab>")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_new_nandsi"
@@ -419,7 +419,7 @@ 
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
    (set_attr "sync_op"              "nand")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_new_<sync_optab><mode>"
@@ -445,7 +445,7 @@ 
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
    (set_attr "sync_op"              "<sync_optab>")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_new_nand<mode>"
@@ -472,7 +472,7 @@ 
    (set_attr "sync_t1"              "0")
    (set_attr "sync_t2"              "3")
    (set_attr "sync_op"              "nand")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_old_<sync_optab>si"
@@ -498,7 +498,7 @@ 
    (set_attr "sync_t1"              "3")
    (set_attr "sync_t2"              "4")
    (set_attr "sync_op"              "<sync_optab>")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_old_nandsi"
@@ -524,7 +524,7 @@ 
    (set_attr "sync_t1"              "3")
    (set_attr "sync_t2"              "4")
    (set_attr "sync_op"              "nand")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" 		    "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_old_<sync_optab><mode>"
@@ -551,7 +551,7 @@ 
    (set_attr "sync_t1"              "3")
    (set_attr "sync_t2"              "4")
    (set_attr "sync_op"              "<sync_optab>")
-   (set_attr "conds" "nocond")
+   (set_attr "conds" 		    "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "arm_sync_old_nand<mode>"
@@ -578,7 +578,7 @@ 
    (set_attr "sync_t1"              "3")
    (set_attr "sync_t2"              "4")
    (set_attr "sync_op"              "nand")
-   (set_attr "conds" "nocond")
+   (set_attr "conds"                "clob")
    (set_attr "predicable" "no")])
 
 (define_insn "*memory_barrier"
diff --git a/gcc/testsuite/gcc.target/arm/sync-1.c b/gcc/testsuite/gcc.target/arm/sync-1.c
new file mode 100644
index 0000000..ad85a04
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/sync-1.c
@@ -0,0 +1,25 @@ 
+/* { dg-do run } */
+/* { dg-options "-O2 -march=armv7-a" } */
+
+volatile int mem;
+
+int
+bar (int x, int y)
+{
+  if (x)
+    __sync_fetch_and_add(&mem, y);
+  return 0;
+}
+
+extern void abort (void);
+
+int
+main (int argc, char *argv[])
+{
+  mem = 0;
+  bar (0, 1);
+  bar (1, 1);
+  if (mem != 1)
+    abort ();
+  return 0;
+}