[PATCH] Fix PR91469

[Richard Biener]

The following fixes PR91469 where STV replaced uses inside address
expressions.  The issue arises here because convert_regs is called
before convert_insns which eventually splits out memory operands.

Bootstrapped / tested on x86_64-unknown-linux-gnu, OK?

Thanks,
Richard.

2019-08-16  Richard Biener  <rguenther@suse.de>

	PR target/91469
	* config/i386/i386-features.c
	(general_scalar_chain::replace_with_subreg): Stop at memory operands.

	* gcc.target/i386/pr91469-1.c: New testcase.
	* gcc.target/i386/pr91469-2.c: Likewise.

Index: gcc/config/i386/i386-features.c
===================================================================
--- gcc/config/i386/i386-features.c	(revision 274536)
+++ gcc/config/i386/i386-features.c	(working copy)
@@ -613,6 +613,10 @@ general_scalar_chain::replace_with_subre
   if (x == reg)
     return gen_rtx_SUBREG (vmode, new_reg, 0);
 
+  /* But not in memory addresses.  */
+  if (MEM_P (x))
+    return x;
+
   const char *fmt = GET_RTX_FORMAT (GET_CODE (x));
   int i, j;
   for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
Index: gcc/testsuite/gcc.target/i386/pr91469-1.c
===================================================================
--- gcc/testsuite/gcc.target/i386/pr91469-1.c	(nonexistent)
+++ gcc/testsuite/gcc.target/i386/pr91469-1.c	(working copy)
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-funroll-loops -O2 -fno-gcse -mavx512vbmi -fno-ivopts -mstv" } */
+
+int a, b, e;
+long long c;
+int d[6];
+
+void fn1() {
+    int i;
+    unsigned f;
+    c = a;
+    f = i;
+    for (; i < b; i++)
+      if (d[i] > f)
+	f = d[i];
+    e = f;
+}
Index: gcc/testsuite/gcc.target/i386/pr91469-2.c
===================================================================
--- gcc/testsuite/gcc.target/i386/pr91469-2.c	(nonexistent)
+++ gcc/testsuite/gcc.target/i386/pr91469-2.c	(working copy)
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Os --param scev-max-expr-size=0 -mavx512vnni -funroll-all-loops" } */
+
+int a, b, c, d;
+int *e;
+void fn1()
+{
+  b = c > 0 ? c : 0;
+  d += e[b];
+  a = d > 0 ? d : 0;
+}