call.without.effects is always possible for CSE #7568
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kripken
reviewed
May 5, 2025
| // call.without.effects is always possible for CSE. | ||
| if (Intrinsics(*getModule()).isCallWithoutEffects(curr)) { | ||
| return true; | ||
| } |
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Hmm, isn't the isGenerative check at the end of the function still important? For example, a call.without.effects might return a random number on each call - that has no effects, but we can't CSE it.
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LocalCSE has a isPossible check to see if an expression can be eliminated. Currently it treats all function calls as not possible. This PR proposes that it should consider "call.without.effects" function calls as always possible.
This will allow reusing result of a previously called without-effect function with the same arguments.