[PATCH 2/2] Handle const_int in expand_single_bit_test

[Andrew Pinski via Gcc-patches]

After expanding directly to rtl instead of
creating a tree, we could end up with
a const_int which is not ready to be handled
by extract_bit_field.
So need to the constant folding here instead.

OK? bootstrapped and tested on x86_64-linux-gnu with no regressions.

        PR middle-end/110117

gcc/ChangeLog:

        * expr.cc (expand_single_bit_test): Handle
        const_int from expand_expr.

gcc/testsuite/ChangeLog:

        * gcc.dg/pr110117-1.c: New test.
        * gcc.dg/pr110117-2.c: New test.
---
 gcc/expr.cc                       | 10 +++++++---
 gcc/testsuite/gcc.dg/pr110117-1.c | 31 +++++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/pr110117-2.c |  7 +++++++
 3 files changed, 45 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr110117-1.c
 create mode 100644 gcc/testsuite/gcc.dg/pr110117-2.c

diff --git a/gcc/expr.cc b/gcc/expr.cc
index ca008cd453e..868d812eb1a 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -12958,12 +12958,16 @@ expand_single_bit_test (location_t loc, enum 
tree_code code,
 
   rtx inner0 = expand_expr (inner, NULL_RTX, VOIDmode, EXPAND_NORMAL);
 
+  if (CONST_SCALAR_INT_P (inner0))
+    {
+      wide_int t = rtx_mode_t (inner0, operand_mode);
+      bool setp = (wi::lrshift(t, bitnum) & 1) != 0;
+      return (setp ^ (code == EQ_EXPR)) ? const1_rtx : const0_rtx;
+    }
   int bitpos = bitnum;
 
-  scalar_int_mode imode = as_a <scalar_int_mode>(GET_MODE (inner0));
-
   if (BYTES_BIG_ENDIAN)
-    bitpos = GET_MODE_BITSIZE (imode) - 1 - bitpos;
+    bitpos = GET_MODE_BITSIZE (operand_mode) - 1 - bitpos;
 
   inner0 = extract_bit_field (inner0, 1, bitpos, 1, target,
                              operand_mode, mode, 0, NULL);
diff --git a/gcc/testsuite/gcc.dg/pr110117-1.c 
b/gcc/testsuite/gcc.dg/pr110117-1.c
new file mode 100644
index 00000000000..fd9a9e3268e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110117-1.c
@@ -0,0 +1,31 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -ftree-vrp -fno-tree-ccp -fno-tree-forwprop" } */
+int a, b, d;
+unsigned c;
+int main() {
+  char e = -10;
+  int f = 1, g = 0;
+  if (a) {
+    char h = e;
+  i:
+    c = ~h - (-g & f || e);
+    int j = b % c;
+    g = j % 9;
+    if (c) {
+      if (d)
+        e = 0;
+      while (!g)
+        ;
+      int k = 0;
+    l:
+      if (k)
+        goto i;
+    }
+  }
+  if (e > -10) {
+    if (g)
+      f = 0;
+    goto l;
+  }
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr110117-2.c 
b/gcc/testsuite/gcc.dg/pr110117-2.c
new file mode 100644
index 00000000000..2e353258084
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110117-2.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fno-tree-dominator-opts -fno-tree-vrp -fno-tree-ccp 
-fno-tree-forwprop -fno-tree-fre -fno-tree-copy-prop" } */
+int f()
+{
+  int t = 0;
+  return (t & 1) != 0;
+}
-- 
2.31.1