; RUN: opt < %s -S -passes='print,loop-unroll,print' 2>&1 | FileCheck %s ; ; This test ensures that (extractvalue 0 (with-overflow-inst op0, op1)) ; is invalidated by LoopPeel when the operands of with-overflow-inst ; are changed. ; ; In the following case, LoopPeel modifies the CFG into another one ; with %bb7 not dominating %bb2 and %bb3 although %extractvalue is ; still the step for the %bb3 loop. %call has been modified and uses ; different operands but the SCEV value for %extractvalue has not been ; invalidated and still refers to %load in its SCEV operands ; (SCEV(%extractvalue) := -2 + -2 * %load). ; ; When LoopUnroll tries to compute the SCEV for the %bb3 Phi, the ; stale data for %extractvalue is used whereas %load is not available ; in %bb3 which is wrong. ; ; for more details and nice pictures: https://github.com/llvm/llvm-project/issues/97586 ; ; Although the reason for the bug was in forgetValue, it is still relevant to ; test if LoopPeel invalidates %extractvalue after changing %call. ; ; forgetValue only walks the users, so calling it on the IV Phis does not ; invalidate %extractvalue (thus forgetLoop does not invalidate it too). ; It has to be done by LoopPeel itself. define void @loop_peeling_smul_with_overflow() { ; before loop-unroll ; CHECK: Classifying expressions for: @loop_peeling_smul_with_overflow ; CHECK: %extractvalue = extractvalue { i32, i1 } %call, 0 ; CHECK-NEXT: --> (-2 + (-2 * %load)) ; CHECK: %phi4 = phi i32 [ %add, %bb3 ], [ 0, %bb2 ] ; CHECK-NEXT: --> {0,+,(-2 + (-2 * %load))}<%bb3> ; after loop-unroll ; CHECK: Classifying expressions for: @loop_peeling_smul_with_overflow ; CHECK: %extractvalue = extractvalue { i32, i1 } %call, 0 ; CHECK-NEXT: --> (-2 * %add8.lcssa) ; CHECK: %phi4 = phi i32 [ %add, %bb3 ], [ 0, %bb2 ] ; CHECK-NEXT: --> {0,+,(-2 * %add8.lcssa)}<%bb3> ; bb: br label %bb1 bb1: ; preds = %bb3, %bb %phi = phi i32 [ 0, %bb ], [ %phi4, %bb3 ] br label %bb5 bb2: ; preds = %bb7 %call = call { i32, i1 } @llvm.smul.with.overflow.i32(i32 %add8, i32 -2) %extractvalue = extractvalue { i32, i1 } %call, 0 br label %bb3 bb3: ; preds = %bb3, %bb2 %phi4 = phi i32 [ %add, %bb3 ], [ 0, %bb2 ] %add = add i32 %extractvalue, %phi4 br i1 false, label %bb3, label %bb1 bb5: ; preds = %bb7, %bb1 %phi6 = phi i32 [ 1, %bb1 ], [ 0, %bb7 ] %icmp = icmp eq i32 %phi, 0 br i1 %icmp, label %bb9, label %bb7 bb7: ; preds = %bb5 %load = load i32, ptr addrspace(1) null, align 4 %add8 = add i32 %load, 1 br i1 false, label %bb2, label %bb5 bb9: ; preds = %bb5 ret void }