178f2eeb13
This is a reland of commit 24e60017d4
The reland changes %ClearFunctionFeedback to clear *all* feedback
slot kinds including binary/compare/for-in slots. In the tests we
thus no longer have to resort to tricks to restore the function to
it's initial state, instead simply call %ClearFunctionFeedback.
Original change's description:
> [maglev] Deopt on overflow in >>>
>
> Re-enable the int32 fast path for ShiftRightLogical, but account for
> Maglev's missing signed/unsigned representation tracking by a)
> removing rhs==0 as the identity value (a shift by 0 is still a
> signed-unsigned conversion) and b) deoptimizing if the result cannot
> be converted to a non-negative smi.
>
> Note this is not a deopt loop, since a non-smi result will change the
> feedback to kSignedSmallInputs (from kSignedSmall).
>
> To fix this properly, we should track signed/unsigned representations
> and convert the result to a heap number if it doesn't fit within smi
> range.
>
> Bug: v8:7700
> Change-Id: Ifd538d227a6f1290eb7f008d9bfad586ff91ea0f
> Fixed: v8:13251
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3876366
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Jakob Linke <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#83025}
Bug: v8:7700
Change-Id: I2f607a0fb863b80e8589c9c1e86ee31fbac48c25
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3879491
Auto-Submit: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Jakob Linke <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83057}
49 lines
1.2 KiB
JavaScript
49 lines
1.2 KiB
JavaScript
// Copyright 2022 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flags: --allow-natives-syntax --maglev
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function gen_shrl_smi(y) {
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return function shrl_smi(x) { return x >>> y; };
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}
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function shrl_test(lhs, rhs, expected_result) {
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const shrl = gen_shrl_smi(rhs);
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// Warmup.
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%PrepareFunctionForOptimization(shrl);
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%ClearFunctionFeedback(shrl);
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shrl(1);
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%OptimizeMaglevOnNextCall(shrl);
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assertEquals(expected_result, shrl(lhs));
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assertTrue(isMaglevved(shrl));
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%DeoptimizeFunction(shrl);
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assertEquals(expected_result, shrl(lhs));
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}
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function shrl_test_expect_deopt(lhs, rhs, expected_result) {
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const shrl = gen_shrl_smi(rhs);
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// Warmup.
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%PrepareFunctionForOptimization(shrl);
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%ClearFunctionFeedback(shrl);
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shrl(1);
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%OptimizeMaglevOnNextCall(shrl);
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assertEquals(expected_result, shrl(lhs));
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assertFalse(isMaglevved(shrl));
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}
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shrl_test(8, 2, 2);
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shrl_test_expect_deopt(-1, 1, 2147483647);
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shrl_test(-8, 2, 1073741822);
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shrl_test_expect_deopt(-8, 0, 4294967288);
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shrl_test_expect_deopt(-892396978, 0, 3402570318);
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shrl_test(8, 10, 0);
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shrl_test(8, 33, 4);
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shrl_test_expect_deopt(0xFFFFFFFF, 0x3FFFFFFF, 1);
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