Index: llvm/trunk/lib/Analysis/InstructionSimplify.cpp =================================================================== --- llvm/trunk/lib/Analysis/InstructionSimplify.cpp +++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp @@ -62,6 +62,8 @@ static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned); static Value *SimplifyCastInst(unsigned, Value *, Type *, const SimplifyQuery &, unsigned); +static Value *SimplifyGEPInst(Type *, ArrayRef, const SimplifyQuery &, + unsigned); /// For a boolean type or a vector of boolean type, return false or a vector /// with every element false. @@ -3491,6 +3493,17 @@ } } + // Same for GEPs. + if (auto *GEP = dyn_cast(I)) { + if (MaxRecurse) { + SmallVector NewOps(GEP->getNumOperands()); + transform(GEP->operands(), NewOps.begin(), + [&](Value *V) { return V == Op ? RepOp : V; }); + return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q, + MaxRecurse - 1); + } + } + // TODO: We could hand off more cases to instsimplify here. // If all operands are constant after substituting Op for RepOp then we can Index: llvm/trunk/test/Transforms/InstSimplify/select.ll =================================================================== --- llvm/trunk/test/Transforms/InstSimplify/select.ll +++ llvm/trunk/test/Transforms/InstSimplify/select.ll @@ -431,3 +431,22 @@ ret i8 %sel } +define i32* @select_icmp_eq_0_gep_operand(i32* %base, i64 %n) { +; CHECK-LABEL: @select_icmp_eq_0_gep_operand( +; CHECK-NEXT: [[GEP:%.*]] = getelementptr +; CHECK-NEXT: ret i32* [[GEP]] + %cond = icmp eq i64 %n, 0 + %gep = getelementptr i32, i32* %base, i64 %n + %r = select i1 %cond, i32* %base, i32* %gep + ret i32* %r +} + +define i32* @select_icmp_ne_0_gep_operand(i32* %base, i64 %n) { +; CHECK-LABEL: @select_icmp_ne_0_gep_operand( +; CHECK-NEXT: [[GEP:%.*]] = getelementptr +; CHECK-NEXT: ret i32* [[GEP]] + %cond = icmp ne i64 %n, 0 + %gep = getelementptr i32, i32* %base, i64 %n + %r = select i1 %cond, i32* %gep, i32* %base + ret i32* %r +}