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From: Aldy Hernandez <>
To: GCC patches <>
Cc: Andrew MacLeod <>,, Aldy Hernandez <>
Subject: [COMMITTED] [PR tree-optimization/107052] range-ops: Pass nonzero masks through cast.
Date: Wed,  5 Oct 2022 14:21:53 +0200	[thread overview]
Message-ID: <> (raw)

Track nonzero masks through a cast in range-ops.

We could also track through a truncating cast if the mask fits in the
outer type.  I will do that as a follow-up patch because I already have
this patchset tested.

	PR tree-optimization/107052


	* (operator_cast::fold_range): Set nonzero mask.
 gcc/ | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gcc/ b/gcc/
index 4f647abd91c..6fa27a8904e 100644
--- a/gcc/
+++ b/gcc/
@@ -2515,6 +2515,14 @@ operator_cast::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
       if (r.varying_p ())
 	return true;
+  // Pass nonzero mask through the cast.
+  if (!truncating_cast_p (inner, outer))
+    {
+      wide_int nz = inner.get_nonzero_bits ();
+      nz = wide_int::from (nz, TYPE_PRECISION (type), TYPE_SIGN (inner.type ()));
+      r.set_nonzero_bits (nz);
+    }
   return true;

             reply	other threads:[~2022-10-05 12:22 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-05 12:21 Aldy Hernandez [this message]
2022-10-05 12:22 Aldy Hernandez

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