[gcc r11-7936] gimple-fold: Recompute ADDR_EXPR flags after folding a TMR [PR98268]

[Richard Sandiford]

https://gcc.gnu.org/g:c778968339afd140380a46edbade054667c7dce2

commit r11-7936-gc778968339afd140380a46edbade054667c7dce2
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Wed Mar 31 19:34:01 2021 +0100

    gimple-fold: Recompute ADDR_EXPR flags after folding a TMR [PR98268]
    
    The gimple verifier picked up that an ADDR_EXPR of a MEM_REF was not
    marked TREE_CONSTANT even though the address was in fact invariant.
    This came from folding a &TARGET_MEM_REF with constant operands to
    a &MEM_REF; &TARGET_MEM_REF is never treated as TREE_CONSTANT
    but &MEM_REF can be.
    
    gcc/
            PR tree-optimization/98268
            * gimple-fold.c (maybe_canonicalize_mem_ref_addr): Call
            recompute_tree_invariant_for_addr_expr after successfully
            folding a TARGET_MEM_REF that occurs inside an ADDR_EXPR.
    
    gcc/testsuite/
            PR tree-optimization/98268
            * gcc.target/aarch64/sve/pr98268-1.c: New test.
            * gcc.target/aarch64/sve/pr98268-2.c: Likewise.

Diff:
---
 gcc/gimple-fold.c                                |  2 ++
 gcc/testsuite/gcc.target/aarch64/sve/pr98268-1.c | 11 +++++++++++
 gcc/testsuite/gcc.target/aarch64/sve/pr98268-2.c | 10 ++++++++++
 3 files changed, 23 insertions(+)

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index de5a6c22395..9e6683dbac9 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -5877,6 +5877,8 @@ maybe_canonicalize_mem_ref_addr (tree *t, bool is_debug = false)
       if (tem)
 	{
 	  *t = tem;
+	  if (TREE_CODE (*orig_t) == ADDR_EXPR)
+	    recompute_tree_invariant_for_addr_expr (*orig_t);
 	  res = true;
 	}
     }
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr98268-1.c b/gcc/testsuite/gcc.target/aarch64/sve/pr98268-1.c
new file mode 100644
index 00000000000..fdbe55e0b4e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr98268-1.c
@@ -0,0 +1,11 @@
+/* { dg-do link } */
+/* { dg-options "-flto -O -ftree-vectorize --param=aarch64-autovec-preference=3" } */
+/* { dg-additional-sources "pr98268-2.c" } */
+
+short d, e;
+void f(char, long*);
+int main() {
+  long x;
+  f(-114, &x);
+  return d == e;
+}
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr98268-2.c b/gcc/testsuite/gcc.target/aarch64/sve/pr98268-2.c
new file mode 100644
index 00000000000..de3b05d5e15
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr98268-2.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O -ftree-vectorize --param=aarch64-autovec-preference=3" } */
+
+extern short d[], e[];
+void f(char a, long *b) {
+  for (int c = 0; c < a - 12; c++) {
+    d[c] = b[c];
+    e[c] = 0;
+  }
+}