[PATCH, GCC-7, GCC-6][ARM][PR target/84826] Backport Fix ICE in extract_insn, at recog.c:2304 on arm-linux-gnueabihf

[Sudakshina Das <sudi dot das at arm dot com>]

Hi

This patch is a request to backport r258777 and r258805 to gcc-7-branch
and gcc-6-branch. The same ICE occurs in both the branches with
-fstack-check. Thus the test case directive has been changed.

The discussion on the patch that went into trunk is:
https://gcc.gnu.org/ml/gcc-patches/2018-03/msg01120.html

Testing : Regtested on both the branches with arm-none-linux-gnueabihf

Is this ok for gcc-7 and gcc-6?

Sudi

ChangeLog entries:

*** gcc/ChangeLog ***

2018-03-28  Sudakshina Das  <sudi.das@arm.com>

        Backport from mainline
        2018-03-22  Sudakshina Das  <sudi.das@arm.com>

        PR target/84826
        * config/arm/arm.h (machine_function): Add 
static_chain_stack_bytes.
        * config/arm/arm.c (arm_compute_static_chain_stack_bytes): Avoid
        re-computing once computed.
        (arm_expand_prologue): Compute machine->static_chain_stack_bytes.
        (arm_init_machine_status): Initialize
        machine->static_chain_stack_bytes.

*** gcc/testsuite/ChangeLog ***

2018-03-28  Sudakshina Das  <sudi.das@arm.com>

	* gcc.target/arm/pr84826.c: Change dg-option to -fstack-check.

        Backport from mainline
        2018-03-23  Sudakshina Das  <sudi.das@arm.com>

        PR target/84826
        * gcc.target/arm/pr84826.c: Add dg directive.

        Backport from mainline
        2018-03-22  Sudakshina Das  <sudi.das@arm.com>

        PR target/84826
        * gcc.target/arm/pr84826.c: New test.

diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 25953f5..68a6fa5 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1420,6 +1420,9 @@ typedef struct GTY(()) machine_function
   machine_mode thumb1_cc_mode;
   /* Set to 1 after arm_reorg has started.  */
   int after_arm_reorg;
+  /* The number of bytes used to store the static chain register on the
+     stack, above the stack frame.  */
+  int static_chain_stack_bytes;
 }
 machine_function;
 #endif
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 6f7ca43..886bcfa 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -19097,6 +19097,11 @@ arm_r3_live_at_start_p (void)
 static int
 arm_compute_static_chain_stack_bytes (void)
 {
+  /* Once the value is updated from the init value of -1, do not
+     re-compute.  */
+  if (cfun->machine->static_chain_stack_bytes != -1)
+    return cfun->machine->static_chain_stack_bytes;
+
   /* See the defining assertion in arm_expand_prologue.  */
   if (IS_NESTED (arm_current_func_type ())
       && ((TARGET_APCS_FRAME && frame_pointer_needed && TARGET_ARM)
@@ -21395,6 +21400,11 @@ arm_expand_prologue (void)
       emit_insn (gen_movsi (stack_pointer_rtx, r1));
     }
 
+  /* Let's compute the static_chain_stack_bytes required and store it.  Right
+     now the value must the -1 as stored by arm_init_machine_status ().  */
+  cfun->machine->static_chain_stack_bytes
+    = arm_compute_static_chain_stack_bytes ();
+
   /* The static chain register is the same as the IP register.  If it is
      clobbered when creating the frame, we need to save and restore it.  */
   clobber_ip = IS_NESTED (func_type)
@@ -24542,6 +24552,7 @@ arm_init_machine_status (void)
 #if ARM_FT_UNKNOWN != 0
   machine->func_type = ARM_FT_UNKNOWN;
 #endif
+  machine->static_chain_stack_bytes = -1;
   return machine;
 }
 
diff --git a/gcc/testsuite/gcc.target/arm/pr84826.c b/gcc/testsuite/gcc.target/arm/pr84826.c
new file mode 100644
index 0000000..563ce51
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr84826.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-Ofast -fstack-check" } */
+
+void d (void *);
+
+void a ()
+{
+  int b;
+  void bar (int c)
+  {
+    if (__builtin_expect (c, 0))
+      ++b;
+  }
+  d (bar);
+}