diff --git a/perl-5.29.0-treat-when-index-1-as-a-boolean-expression.patch b/perl-5.29.0-treat-when-index-1-as-a-boolean-expression.patch
new file mode 100644
index 0000000..7d39d49
--- /dev/null
+++ b/perl-5.29.0-treat-when-index-1-as-a-boolean-expression.patch
@@ -0,0 +1,103 @@
+From 6b877bbd2c071b3e0659fab552a74dc2ff7e08fb Mon Sep 17 00:00:00 2001
+From: David Mitchell <davem@iabyn.com>
+Date: Sat, 14 Jul 2018 10:47:04 +0100
+Subject: [PATCH] treat when(index() > -1) as a boolean expression
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+RT #133368
+
+when(X) is normally compiled as when($_ ~~ X) *except* when X appears to
+be a boolean expression, in which case it's used directly.
+
+5.28.0 introduced an optimisation whereby comparisons involving index
+like
+
+    index(...) != -1
+
+eliminated the comparison, and pp_index() returned a boolean value
+directly. This defeated the 'look for a boolean op' mechanism, and so
+
+    when(index(...) != -1)
+
+and similar were being incorrectly compiled as
+
+    when($_ ~~ (index(...) != -1))
+
+Signed-off-by: Petr Písař <ppisar@redhat.com>
+---
+ op.c          |  8 +++++++-
+ t/op/switch.t | 23 ++++++++++++++++++++++-
+ 2 files changed, 29 insertions(+), 2 deletions(-)
+
+diff --git a/op.c b/op.c
+index a05a1319d4..ddeb484b64 100644
+--- a/op.c
++++ b/op.c
+@@ -9072,6 +9072,13 @@ S_looks_like_bool(pTHX_ const OP *o)
+ 	case OP_FLOP:
+ 
+ 	    return TRUE;
++
++	case OP_INDEX:
++	case OP_RINDEX:
++            /* optimised-away (index() != -1) or similar comparison */
++            if (o->op_private & OPpTRUEBOOL)
++                return TRUE;
++            return FALSE;
+ 	
+ 	case OP_CONST:
+ 	    /* Detect comparisons that have been optimized away */
+@@ -9081,7 +9088,6 @@ S_looks_like_bool(pTHX_ const OP *o)
+ 		return TRUE;
+ 	    else
+ 		return FALSE;
+-
+ 	/* FALLTHROUGH */
+ 	default:
+ 	    return FALSE;
+diff --git a/t/op/switch.t b/t/op/switch.t
+index e5385df0b4..6ff69e0bce 100644
+--- a/t/op/switch.t
++++ b/t/op/switch.t
+@@ -10,7 +10,7 @@ use strict;
+ use warnings;
+ no warnings 'experimental::smartmatch';
+ 
+-plan tests => 195;
++plan tests => 197;
+ 
+ # The behaviour of the feature pragma should be tested by lib/feature.t
+ # using the tests in t/lib/feature/*. This file tests the behaviour of
+@@ -1358,6 +1358,27 @@ given("xyz") {
+ 	"scalar value of false when";
+ }
+ 
++# RT #133368
++# index() and rindex() comparisons such as '> -1' are optimised away. Make
++# sure that they're still treated as a direct boolean expression rather
++# than when(X) being implicitly converted to when($_ ~~ X)
++
++{
++    my $s = "abc";
++    my $ok = 0;
++    given("xyz") {
++        when (index($s, 'a') > -1) { $ok = 1; }
++    }
++    ok($ok, "RT #133368 index");
++
++    $ok = 0;
++    given("xyz") {
++        when (rindex($s, 'a') > -1) { $ok = 1; }
++    }
++    ok($ok, "RT #133368 rindex");
++}
++
++
+ # Okay, that'll do for now. The intricacies of the smartmatch
+ # semantics are tested in t/op/smartmatch.t. Taintedness of
+ # returned values is checked in t/op/taint.t.
+-- 
+2.14.4
+
diff --git a/perl.spec b/perl.spec
index 6f39f48..5fe45ec 100644
--- a/perl.spec
+++ b/perl.spec
@@ -81,7 +81,7 @@ License:        GPL+ or Artistic
 Epoch:          %{perl_epoch}
 Version:        %{perl_version}
 # release number must be even higher, because dual-lived modules will be broken otherwise
-Release:        418%{?dist}
+Release:        419%{?dist}
 Summary:        Practical Extraction and Report Language
 Url:            https://www.perl.org/
 Source0:        https://www.cpan.org/src/5.0/perl-%{perl_version}.tar.xz
@@ -164,6 +164,10 @@ Patch17:        perl-5.29.0-regexec.c-Call-macro-with-correct-args.patch
 # Fix invoking a check for wide characters while ISO-8859-1 locale is in effect
 Patch18:        perl-5.29.0-perl.h-Add-parens-around-macro-arguments.patch
 
+# Fix index() and rindex() optimization in given-when boolean context,
+# RT#133368, in upstream after 5.29.0
+Patch19:        perl-5.29.0-treat-when-index-1-as-a-boolean-expression.patch
+
 # Link XS modules to libperl.so with EU::CBuilder on Linux, bug #960048
 Patch200:       perl-5.16.3-Link-XS-modules-to-libperl.so-with-EU-CBuilder-on-Li.patch
 
@@ -2736,6 +2740,7 @@ Perl extension for Version Objects
 %patch16 -p1
 %patch17 -p1
 %patch18 -p1
+%patch19 -p1
 %patch200 -p1
 %patch201 -p1
 
@@ -2761,6 +2766,7 @@ perl -x patchlevel.h \
     'Fedora Patch16: Fix an integer wrap when allocating memory for an environment variable (RT#133204)' \
     'Fedora Patch17: Fix printing a warning about a wide character when matching a regular expression while ISO-8859-1 locale is in effect' \
     'Fedora Patch18: Fix invoking a check for wide characters while ISO-8859-1 locale is in effect' \
+    'Fedora Patch19: Fix index() and rindex() optimization in given-when boolean context (RT#133368)' \
     'Fedora Patch200: Link XS modules to libperl.so with EU::CBuilder on Linux' \
     'Fedora Patch201: Link XS modules to libperl.so with EU::MM on Linux' \
     %{nil}
@@ -5049,6 +5055,10 @@ popd
 
 # Old changelog entries are preserved in CVS.
 %changelog
+* Tue Jul 17 2018 Petr Pisar <ppisar@redhat.com> - 4:5.28.0-419
+- Fix index() and rindex() optimization in given-when boolean context
+  (RT#133368)
+
 * Fri Jul 13 2018 Fedora Release Engineering <releng@fedoraproject.org> - 4:5.28.0-418
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass_Rebuild