[gcc r14-4113] MATCH: Avoid recursive zero_one_valued_p for conversions

[gcc r14-4113] MATCH: Avoid recursive zero_one_valued_p for conversions

[Andrew Pinski]

https://gcc.gnu.org/g:951d3c191d01440ad54415f683437770b0c957e4

commit r14-4113-g951d3c191d01440ad54415f683437770b0c957e4
Author: Andrew Pinski <apinski@marvell.com>
Date:   Sat Sep 16 15:19:58 2023 -0700

    MATCH: Avoid recursive zero_one_valued_p for conversions
    
    So when VN finds a name which has a nop conversion, it says
    both names are equivalent to each other and the valuaization
    function for one will return the other. This normally does not
    cause any issues as there is no recursive matches. But after
    r14-4038-gb975c0dc3be285, there was one added. So we would
    do an infinite recursion on the match and never finish.
    This fixes the issue (and adds a comment in match.pd) by
    for converts just handle one level instead of being recursive
    always.
    
    OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
    
    Note the testcase was reduced from tree-ssa-loop-niter.cc and then
    changed slightly into C rather than C++ but it still needs exceptions
    turned on get the IR that VN would produce this equivalence relationship
    going on. Also had to turn off early inline to force put to be inlined later.
    
            PR tree-optimization/111435
    
    gcc/ChangeLog:
    
            * match.pd (zero_one_valued_p): Don't do recursion
            on converts.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.c-torture/compile/pr111435-1.c: New test.

Diff:
---
 gcc/match.pd                                     |  8 +++++++-
 gcc/testsuite/gcc.c-torture/compile/pr111435-1.c | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index a05d4f07ab5..a405c9ff6f8 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2188,8 +2188,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* A conversion from an zero_one_valued_p is still a [0,1].
    This is useful when the range of a variable is not known */
+/* Note this matches can't be recursive because of the way VN handles
+   nop conversions being equivalent and then recursive between them. */
 (match zero_one_valued_p
- (convert@0 zero_one_valued_p))
+ (convert@0 @1)
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
+      && (TYPE_UNSIGNED (TREE_TYPE (@1))
+	  || TYPE_PRECISION (TREE_TYPE (@1)) > 1)
+      && wi::leu_p (tree_nonzero_bits (@1), 1))))
 
 /* Transform { 0 or 1 } * { 0 or 1 } into { 0 or 1 } & { 0 or 1 }.  */
 (simplify
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr111435-1.c b/gcc/testsuite/gcc.c-torture/compile/pr111435-1.c
new file mode 100644
index 00000000000..afa84dd59dd
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr111435-1.c
@@ -0,0 +1,18 @@
+/* { dg-options "-fexceptions -fno-early-inlining" } */
+/* { dg-require-effective-target exceptions } */
+
+void find_slot_with_hash(const int *);
+
+void put(const int *k, const int *) {
+    find_slot_with_hash(k);
+}
+unsigned len();
+int *address();
+void h(int header, int **bounds) {
+  if (!*bounds)
+    return;
+  unsigned t = *bounds ? len() : 0;
+  int queue_index = t;
+  address()[(unsigned)queue_index] = 0;
+  put(&header, &queue_index);
+}