942258 - Assertion failure: mir->canBeDivideByZero(), at jit/shared/CodeGenerator-x86-shared.cpp

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Attachment: stack

function f(x) {
    y(((x >>> 0) / (x >>> 0)) >> 0)
}
for (var i = 0; i < 2; i++) {
    try {
        f(Number.MAX_VALUE)
    } catch (e) {}
}
function g() {
    x ? (x ? (f(0x80000000, y) ? f : 0) : x) : y
}
g()

asserts js debug shell on m-c changeset c7cbfa315d46 with --ion-eager at Assertion failure: mir->canBeDivideByZero(), at jit/shared/CodeGenerator-x86-shared.cpp

My configure flags are:

CC="clang -Qunused-arguments" AR=ar CXX="clang++ -Qunused-arguments" sh ./configure --target=x86_64-apple-darwin12.5.0 --enable-optimize --enable-debug --enable-profiling --enable-gczeal --enable-debug-symbols --enable-methodjit --enable-type-inference --disable-tests --with-ccache --disable-threadsafe

Comment 1

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

autoBisect shows this is probably related to the following changeset:

The first bad revision is:
changeset:   http://hg.mozilla.org/mozilla-central/rev/2a5427c3a4ba
user:        Dan Gohman
date:        Wed Nov 20 21:53:51 2013 -0800
summary:     Bug 939893 - IonMonkey: Handle x/x in lowerUDiv. r=bhackett

Dan, is bug 939893 a likely regressor?

Comment 2

[Dan Gohman [:sunfish]]

Attachment: fix-div-self.patch

Comment 3

[Dan Gohman [:sunfish]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/caec531a513b

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/caec531a513b