On 9/1/23 11:30, Andrew Pinski via Gcc-patches wrote:
So it turns out there was a simplier way of starting to
improve VRP to start to fix PR 110131, PR 108360, and PR 108397.
That was rewrite test_for_singularity to use range_op_handler
and Value_Range.
This patch implements that and
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
* vr-values.cc (test_for_singularity): Add edge argument
and rewrite using range_op_handler.
(simplify_compare_using_range_pairs): Use Value_Range
instead of value_range and update test_for_singularity call.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/vrp124.c: New test.
* gcc.dg/tree-ssa/vrp125.c: New test.
---
diff --git a/gcc/vr-values.cc b/gcc/vr-values.cc
index 52ab4fe6109..2474e57ee90 100644
--- a/gcc/vr-values.cc
+++ b/gcc/vr-values.cc
@@ -904,69 +904,33 @@ simplify_using_ranges::simplify_bit_ops_using_ranges
}
/* We are comparing trees OP1 and OP2 using COND_CODE. OP1 has
- a known value range VR.
+ a known value range OP1_RANGE.
If there is one and only one value which will satisfy the
- conditional, then return that value. Else return NULL.
-
- If signed overflow must be undefined for the value to satisfy
- the conditional, then set *STRICT_OVERFLOW_P to true. */
+ conditional on the EDGE, then return that value.
+ Else return NULL. */
static tree
test_for_singularity (enum tree_code cond_code, tree op1,
- tree op2, const value_range *vr)
+ tree op2, const int_range_max &op1_range, bool edge)
{
- tree min = NULL;
- tree max = NULL;
-
- /* Extract minimum/maximum values which satisfy the conditional as it was
- written. */
- if (cond_code == LE_EXPR || cond_code == LT_EXPR)
+ /* This is already a singularity. */
+ if (cond_code == NE_EXPR || cond_code == EQ_EXPR)
+ return NULL;
I don't think this is necessarily the right thing to do for NE.
Consider if op1 has the range [0,1] and op2 has the value 1. If the
code is NE, then we should be able to return a singularity of 0 since
that's the only value for x where x ne 1 is true given the range for x.
I like what you're trying to do, it just needs a bit of refinement I think.
jeff
