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wasm2js: Do not convert x >>> 0 | 0 to x >>> 0 #2581

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Merged
merged 2 commits into from
Jan 10, 2020
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wasm2js: Do not convert x >>> 0 | 0 to x >>> 0 #2581

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77b6093
wasm2js: Do not convert x >>> 0 | 0 to x >>> 0. Fixes emscripten-cor…
kripken Jan 9, 2020
5418c50
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kripken Jan 9, 2020
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12 changes: 10 additions & 2 deletions src/tools/wasm2js.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -179,6 +179,14 @@ static void optimizeJS(Ref ast) {
return false;
};

auto isSignedBitwise = [](Ref node) {
if (node->isArray() && !node->empty() && node[0] == BINARY) {
auto op = node[1];
return op == OR || op == AND || op == XOR || op == RSHIFT || op == LSHIFT;
}
return false;
};

auto isUnary = [](Ref node, IString op) {
return node->isArray() && !node->empty() && node[0] == UNARY_PREFIX &&
node[1] == op;
Expand Down Expand Up @@ -275,9 +283,9 @@ static void optimizeJS(Ref ast) {
// x | 0 going into a bitwise op => skip the | 0
node[2] = removeOrZero(node[2]);
node[3] = removeOrZero(node[3]);
// x | 0 | 0 => x | 0
// (x | 0 or similar) | 0 => (x | 0 or similar)
if (isOrZero(node)) {
if (isBitwise(node[2])) {
if (isSignedBitwise(node[2])) {
replaceInPlace(node, node[2]);
}
}
Expand Down
8 changes: 4 additions & 4 deletions test/wasm2js/conversions-modified.2asm.js.opt
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Expand Up @@ -60,7 +60,7 @@ function asmFunc(global, env, buffer) {

function $4($0) {
$0 = Math_fround($0);
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $5($0) {
Expand All @@ -70,19 +70,19 @@ function asmFunc(global, env, buffer) {

function $6($0) {
$0 = +$0;
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $7($0) {
$0 = Math_fround($0);
i64toi32_i32$HIGH_BITS = Math_fround(Math_abs($0)) >= Math_fround(1.0) ? ($0 > Math_fround(0.0) ? ~~Math_fround(Math_min(Math_fround(Math_floor(Math_fround($0 / Math_fround(4294967296.0)))), Math_fround(4294967296.0))) >>> 0 : ~~Math_fround(Math_ceil(Math_fround(Math_fround($0 - Math_fround(~~$0 >>> 0 >>> 0)) / Math_fround(4294967296.0)))) >>> 0) : 0;
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $9($0) {
$0 = +$0;
i64toi32_i32$HIGH_BITS = Math_abs($0) >= 1.0 ? ($0 > 0.0 ? ~~Math_min(Math_floor($0 / 4294967296.0), 4294967295.0) >>> 0 : ~~Math_ceil(($0 - +(~~$0 >>> 0 >>> 0)) / 4294967296.0) >>> 0) : 0;
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $11($0) {
Expand Down
4 changes: 2 additions & 2 deletions test/wasm2js/float-ops.2asm.js.opt
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Expand Up @@ -236,12 +236,12 @@ function asmFunc(global, env, buffer) {

function $41($0) {
$0 = Math_fround($0);
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $42($0) {
$0 = +$0;
return ~~$0 >>> 0;
return ~~$0 >>> 0 | 0;
}

function $47($0) {
Expand Down
16 changes: 8 additions & 8 deletions test/wasm2js/i64-rotate.2asm.js.opt
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Expand Up @@ -35,9 +35,9 @@ function asmFunc(global, env, buffer) {
$5 = $6;
$3 = $5 & 31;
if (32 <= $5 >>> 0) {
$3 = -1 >>> $3
$3 = -1 >>> $3 | 0
} else {
$4 = -1 >>> $3;
$4 = -1 >>> $3 | 0;
$3 = (1 << $3) - 1 << 32 - $3 | -1 >>> $3;
}
$5 = $3 & $0;
Expand Down Expand Up @@ -66,9 +66,9 @@ function asmFunc(global, env, buffer) {
$1 = $4 & 31;
if (32 <= $4 >>> 0) {
$2 = 0;
$0 = $3 >>> $1;
$0 = $3 >>> $1 | 0;
} else {
$2 = $3 >>> $1;
$2 = $3 >>> $1 | 0;
$0 = ((1 << $1) - 1 & $3) << 32 - $1 | $0 >>> $1;
}
$0 = $0 | $6;
Expand All @@ -92,19 +92,19 @@ function asmFunc(global, env, buffer) {
$5 = $6 & 31;
if (32 <= $6 >>> 0) {
$4 = 0;
$6 = $3 >>> $5;
$6 = $3 >>> $5 | 0;
} else {
$4 = $3 >>> $5;
$4 = $3 >>> $5 | 0;
$6 = ((1 << $5) - 1 & $3) << 32 - $5 | $7 >>> $5;
}
$7 = $4;
$3 = 0 - $2 & 63;
$5 = $3 & 31;
if (32 <= $3 >>> 0) {
$4 = 0;
$2 = -1 >>> $5;
$2 = -1 >>> $5 | 0;
} else {
$4 = -1 >>> $5;
$4 = -1 >>> $5 | 0;
$2 = (1 << $5) - 1 << 32 - $5 | -1 >>> $5;
}
$0 = $2 & $0;
Expand Down
8 changes: 4 additions & 4 deletions test/wasm2js/stack-modified.2asm.js.opt
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Original file line number Diff line number Diff line change
Expand Up @@ -52,15 +52,15 @@ function asmFunc(global, env, buffer) {

function _ZN17compiler_builtins3int3mul3Mul3mul17h070e9a1c69faec5bE($0_1, $1, $2, $3) {
var $4 = 0, $5 = 0, $6 = 0, $7 = 0, $8 = 0, $9 = 0;
$4 = $2 >>> 16;
$5 = $0_1 >>> 16;
$4 = $2 >>> 16 | 0;
$5 = $0_1 >>> 16 | 0;
$9 = Math_imul($4, $5);
$6 = $2 & 65535;
$7 = $0_1 & 65535;
$8 = Math_imul($6, $7);
$5 = ($8 >>> 16) + Math_imul($5, $6) | 0;
$5 = ($8 >>> 16 | 0) + Math_imul($5, $6) | 0;
$4 = ($5 & 65535) + Math_imul($4, $7) | 0;
$0_1 = (((Math_imul($1, $2) + $9 | 0) + Math_imul($0_1, $3) | 0) + ($5 >>> 16) | 0) + ($4 >>> 16) | 0;
$0_1 = (Math_imul($1, $2) + $9 | 0) + Math_imul($0_1, $3) + ($5 >>> 16) + ($4 >>> 16) | 0;
$1 = $8 & 65535 | $4 << 16;
i64toi32_i32$HIGH_BITS = $0_1;
return $1;
Expand Down