[PATCH] D38856: [IPSCCP] Remove calls without side effects

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added inline comments.


================
Comment at: lib/Transforms/Scalar/SCCP.cpp:1929
         if (tryToReplaceWithConstant(Solver, Inst)) {
-          if (!isa<CallInst>(Inst) && !isa<TerminatorInst>(Inst))
+          if ((!isa<CallInst>(Inst) || !Inst->mayHaveSideEffects()) &&
+              !isa<TerminatorInst>(Inst))
----------------
Can we just make this `!Inst->mayHaveSideEffects() && !isa<TerminatorInst>(Inst)`?  Otherwise we're assuming that non-calls that aren't terminators are not side effecting, which may be correct specifically for the instructions that `tryToReplaceWithConstant` returns true for, but isn't true in general.


https://reviews.llvm.org/D38856