[PATCH] tree-optimization/110496 - TYPE_PRECISION issue with store-merging

[Richard Biener via Gcc-patches]

When store-merging looks for bswap opportunities we also handle
BIT_FIELD_REFs where we verify the refed object is of scalar
type but we don't check for the result type we eventually use.
That's done later but after we eventually query TYPE_PRECISION.
The following re-orders this.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

        PR tree-optimization/110496
        * gimple-ssa-store-merging.cc (find_bswap_or_nop_1): Re-order
        verifying and TYPE_PRECISION query for the BIT_FIELD_REF case.

        * gcc.dg/pr110496.c: New testcase.
---
 gcc/gimple-ssa-store-merging.cc |  5 ++++-
 gcc/testsuite/gcc.dg/pr110496.c | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr110496.c

diff --git a/gcc/gimple-ssa-store-merging.cc b/gcc/gimple-ssa-store-merging.cc
index 401496a9231..0d19b98ed73 100644
--- a/gcc/gimple-ssa-store-merging.cc
+++ b/gcc/gimple-ssa-store-merging.cc
@@ -650,10 +650,13 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number 
*n, int limit)
 
          /* Convert.  */
          n->type = TREE_TYPE (rhs1);
+         if (!verify_symbolic_number_p (n, stmt))
+           return NULL;
+
          if (!n->base_addr)
            n->range = TYPE_PRECISION (n->type) / BITS_PER_UNIT;
 
-         return verify_symbolic_number_p (n, stmt) ? stmt : NULL;
+         return stmt;
        }
 
       return NULL;
diff --git a/gcc/testsuite/gcc.dg/pr110496.c b/gcc/testsuite/gcc.dg/pr110496.c
new file mode 100644
index 00000000000..3c3d12fb532
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110496.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+long contents, f_num;
+int decide();
+int f_MV0__x;
+void f() {
+  unsigned char *rptr;
+  unsigned char valbuf[6];
+  rptr = (unsigned char *)contents;
+  if (decide())
+    do {
+      __builtin_memcpy(valbuf, &f_MV0__x, sizeof(int));
+      (&valbuf[0])[4] = (&valbuf[0])[5] = 0;
+    } while (0);
+  else {
+    int MV0__x = f_num;
+    __builtin_memcpy(valbuf, &MV0__x, sizeof(int));
+    (&valbuf[0])[4] = (&valbuf[0])[5] = 0;
+  }
+  rptr[1] = valbuf[4];
+  rptr[2] = valbuf[5];
+  rptr[4] = valbuf[1];
+  rptr[5] = valbuf[2];
+  __builtin_memset(valbuf, 0, 8);
+}
-- 
2.35.3