From b53c2382a9a56e7dd210d6798e97b7aee4d9ac5d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 24 Oct 2005 06:22:12 +0000 Subject: [PATCH] Before promoting a malloc type, remove dead uses. This makes instcombine more effective at promoting these allocations, catching them earlier in the compile process. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23959 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../Scalar/InstructionCombining.cpp | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 4c6b6a82d7d..09fee7cc4bd 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3769,6 +3769,26 @@ Instruction *InstCombiner::PromoteCastOfAllocation(CastInst &CI, const PointerType *PTy = dyn_cast(CI.getType()); if (AI.isArrayAllocation() || !PTy) return 0; + // Remove any uses of AI that are dead. + assert(!CI.use_empty() && "Dead instructions should be removed earlier!"); + std::vector DeadUsers; + for (Value::use_iterator UI = AI.use_begin(), E = AI.use_end(); UI != E; ) { + Instruction *User = cast(*UI++); + if (isInstructionTriviallyDead(User)) { + while (UI != E && *UI == User) + ++UI; // If this instruction uses AI more than once, don't break UI. + + // Add operands to the worklist. + AddUsesToWorkList(*User); + ++NumDeadInst; + DEBUG(std::cerr << "IC: DCE: " << *User); + + User->eraseFromParent(); + removeFromWorkList(User); + } + } + + // Finally, if the instruction now has one use, delete it. if (!AI.hasOneUse()) return 0; // Get the type really allocated and the type casted to. -- 2.34.1