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62 lines
1.7 KiB
62 lines
1.7 KiB
From 4e82c85b1c9c9b30253b8624470da6f20a6c0604 Mon Sep 17 00:00:00 2001 |
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From: Karl Williamson <khw@cpan.org> |
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Date: Mon, 15 Mar 2021 21:01:47 -0600 |
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Subject: [PATCH] Fix broken left shift of IV_MIN under 'use integer' |
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MIME-Version: 1.0 |
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Content-Type: text/plain; charset=UTF-8 |
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Content-Transfer-Encoding: 8bit |
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This fixes GH 18639 |
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When I wrote this code, I conflated casting and complementing. |
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Signed-off-by: Petr Písař <ppisar@redhat.com> |
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--- |
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pp.c | 3 --- |
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t/op/bop.t | 9 ++++++++- |
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2 files changed, 8 insertions(+), 4 deletions(-) |
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diff --git a/pp.c b/pp.c |
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index d365afea4c..baf0777a47 100644 |
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--- a/pp.c |
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+++ b/pp.c |
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@@ -2007,9 +2007,6 @@ static IV S_iv_shift(IV iv, int shift, bool left) |
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* 18446744073709551552 |
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* */ |
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if (left) { |
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- if (iv == IV_MIN) { /* Casting this to a UV is undefined behavior */ |
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- return 0; |
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- } |
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return (IV) (((UV) iv) << shift); |
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} |
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diff --git a/t/op/bop.t b/t/op/bop.t |
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index 07f057d0a9..31b6531a03 100644 |
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--- a/t/op/bop.t |
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+++ b/t/op/bop.t |
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@@ -18,7 +18,7 @@ BEGIN { |
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# If you find tests are failing, please try adding names to tests to track |
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# down where the failure is, and supply your new names as a patch. |
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# (Just-in-time test naming) |
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-plan tests => 502; |
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+plan tests => 503; |
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# numerics |
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ok ((0xdead & 0xbeef) == 0x9ead); |
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@@ -33,6 +33,13 @@ ok ((33023 >> 7) == 257); |
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# signed vs. unsigned |
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ok ((~0 > 0 && do { use integer; ~0 } == -1)); |
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+{ # GH #18639 |
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+ my $iv_min = -(~0 >> 1) - 1; |
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+ my $shifted; |
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+ { use integer; $shifted = $iv_min << 0 }; |
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+ is($shifted, $iv_min, "IV_MIN << 0 yields IV_MIN under 'use integer'"); |
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+} |
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+ |
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my $bits = 0; |
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for (my $i = ~0; $i; $i >>= 1) { ++$bits; } |
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my $cusp = 1 << ($bits - 1); |
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-- |
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2.26.3 |
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