Fix GH-14873: PHP 8.4 min function fails on typed integer #14876
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nielsdos
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The DFA pass may cause the op1 and result argument to be equal to each other. In the VM we always use ZVAL_NULL(result) first, which will also destroy the first argument. Use a temporary result to fix the issue.
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I wonder if it might be easier to adjust the DFA pass instead, by special casing frameless calls. This would also avoid the copy in the VM. |
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Maybe. Then you do have an extra copy opline though from the temporary return value to the CV AFAIK |
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@nielsdos Not having looked at this yet, it seems that was mostly the case anyway, given we haven't seen any other failures, right? |
That is true. |
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max() is in fact affected. The bug is not in the min/max implementation but either in the optimizer of the VM/JIT depending on the PoV. |
The problem is that this line in the VM: `ZVAL_NULL(result);` changes the type of arg1 as well, because after the DFA pass the result and input both use CV0($result). We should not contract assignments with CVs in frameless calls with arguments. An older attempt is found at phpGH-14876 that tried to modify the VM/JIT.
The problem is that this line in the VM: `ZVAL_NULL(result);` changes the type of arg1 as well, because after the DFA pass the result and input both use CV0($result). We should not contract assignments with CVs in frameless calls with arguments. An older attempt is found at phpGH-14876 that tried to modify the VM/JIT.
The problem is that this line in the VM: `ZVAL_NULL(result);` changes the type of arg1 as well, because after the DFA pass the result and input both use CV0($result). We should not contract assignments with CVs in frameless calls with arguments. An older attempt is found at GH-14876 that tried to modify the VM/JIT. Closes GH-14903.
The DFA pass may cause the op1 and result argument to be equal to each other. In the VM we always use ZVAL_NULL(result) first, which will also destroy the first argument. Use a temporary result to fix the issue.