commit 5fdcac79eb72406c59fa72073dfb3ba21380f56d
Author: ktkachov <ktkachov@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Tue Apr 10 09:58:57 2018 +0000

    [explow] PR target/85173: validize memory before passing it on to target probe_stack
    
    In this PR the expansion code emits an invalid memory address for the stack probe, which the backend fails to recognise.
    The address is created explicitly in anti_adjust_stack_and_probe_stack_clash in explow.c and passed down to gen_probe_stack
    without any validation in emit_stack_probe.
    
    This patch fixes the ICE by calling validize_mem on the memory location before passing it down to the target.
    Jakub pointed out that we also want to create valid addresses for the probe_stack_address case, so this patch
    creates an expand operand and legitimizes it before passing it down to the probe_stack_address expander.
    
    This patch passes bootstrap and testing on arm-none-linux-gnueabihf and aarch64-none-linux-gnu
    and ppc64le-redhat-linux on gcc112 in the compile farm.
    
            PR target/85173
            * explow.c (emit_stack_probe): Call validize_mem on memory location
            before passing it to gen_probe_stack.  Create address operand and
            legitimize it for the probe_stack_address case.
    
            * gcc.target/arm/pr85173.c: New test.
    
    
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@259266 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/explow.c b/gcc/explow.c
index 9386489..e2253ae 100644
--- a/gcc/explow.c
+++ b/gcc/explow.c
@@ -1549,13 +1549,20 @@ emit_stack_probe (rtx address)
 {
 #ifdef HAVE_probe_stack_address
   if (HAVE_probe_stack_address)
-    emit_insn (gen_probe_stack_address (address));
+    {
+      struct expand_operand ops[1];
+      insn_code icode = targetm.code_for_probe_stack_address;
+      create_address_operand (ops, address);
+      maybe_legitimize_operands (icode, 0, 1, ops);
+      expand_insn (icode, 1, ops);
+    }
   else
 #endif
     {
       rtx memref = gen_rtx_MEM (word_mode, address);
 
       MEM_VOLATILE_P (memref) = 1;
+      memref = validize_mem (memref);
 
       /* See if we have an insn to probe the stack.  */
 #ifdef HAVE_probe_stack
diff --git a/gcc/testsuite/gcc.target/arm/pr85173.c b/gcc/testsuite/gcc.target/arm/pr85173.c
new file mode 100644
index 0000000..36105c9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr85173.c
@@ -0,0 +1,20 @@
+/* PR target/85173.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-clash-protection --param stack-clash-protection-probe-interval=14" } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+
+__attribute__((noinline, noclone)) void
+foo (char *p)
+{
+  asm volatile ("" : : "r" (p) : "memory");
+}
+
+/* Nonconstant alloca, small local frame.  */
+__attribute__((noinline, noclone)) void
+f5 (int x)
+{
+  char locals[128];
+  char *vla = __builtin_alloca (x);
+  foo (vla);
+}