From d057a97cb1ddacbc501ea3bbd08e94f32ef7eaa9 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Thu, 5 Jun 2025 23:12:34 +0800 Subject: [PATCH 1/2] [LoopPeel] Handle non-local instructions/arguments when updating exit values --- llvm/lib/Transforms/Utils/LoopPeel.cpp | 6 ++- .../unroll-and-peel-last-iteration.ll | 41 +++++++++++++++++++ 2 files changed, 46 insertions(+), 1 deletion(-) diff --git a/llvm/lib/Transforms/Utils/LoopPeel.cpp b/llvm/lib/Transforms/Utils/LoopPeel.cpp index bd025fddd0cf7..9149f71941db4 100644 --- a/llvm/lib/Transforms/Utils/LoopPeel.cpp +++ b/llvm/lib/Transforms/Utils/LoopPeel.cpp @@ -1257,7 +1257,11 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, bool PeelLast, LoopInfo *LI, // Now adjust users of the original exit values by replacing them with the // exit value from the peeled iteration and remove them. for (const auto &[P, E] : ExitValues) { - P->replaceAllUsesWith(isa(E) ? E : &*VMap.lookup(E)); + Instruction *ExitInst = dyn_cast(E); + if (ExitInst && L->contains(ExitInst)) + P->replaceAllUsesWith(&*VMap[ExitInst]); + else + P->replaceAllUsesWith(E); P->eraseFromParent(); } formLCSSA(*L, DT, LI, SE); diff --git a/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll b/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll index 7d38c18d10667..f07afaf1b207f 100644 --- a/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll +++ b/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll @@ -71,6 +71,47 @@ exit: ret i32 %1 } +; Test case for https://github.com/llvm/llvm-project/issues/142895. + +define i32 @pr142895_exit_value_is_arg(i32 %arg) { +entry: + br label %for.cond.preheader + +for.cond.preheader: + %indvar = phi i32 [ 0, %entry ], [ %inc, %for.cond.preheader ] + %cmp1 = icmp eq i32 %indvar, 32 + %sel = select i1 %cmp1, i32 0, i32 0 + %sub = sub i32 0, 0 + %xor = xor i32 0, 0 + %inc = add i32 %indvar, 1 + %exitcond = icmp ne i32 %inc, 33 + br i1 %exitcond, label %for.cond.preheader, label %for.cond.cleanup + +for.cond.cleanup: + %exit.lcssa = phi i32 [ %arg, %for.cond.preheader ] + ret i32 %exit.lcssa +} + +define i32 @pr142895_exit_value_is_inst(i32 %arg) { +entry: + %mul = mul i32 %arg, 7 + br label %for.cond.preheader + +for.cond.preheader: + %indvar = phi i32 [ 0, %entry ], [ %inc, %for.cond.preheader ] + %cmp1 = icmp eq i32 %indvar, 32 + %sel = select i1 %cmp1, i32 0, i32 0 + %sub = sub i32 0, 0 + %xor = xor i32 0, 0 + %inc = add i32 %indvar, 1 + %exitcond = icmp ne i32 %inc, 33 + br i1 %exitcond, label %for.cond.preheader, label %for.cond.cleanup + +for.cond.cleanup: + %exit.lcssa = phi i32 [ %mul, %for.cond.preheader ] + ret i32 %exit.lcssa +} + declare void @foo(i32) ;. ; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]]} From e1c547542c4dda027205abffa38bfbc2846b980a Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Fri, 6 Jun 2025 00:04:25 +0800 Subject: [PATCH 2/2] [LoopPeel] Update tests. NFC. --- .../unroll-and-peel-last-iteration.ll | 81 ++++++++++++++++--- 1 file changed, 69 insertions(+), 12 deletions(-) diff --git a/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll b/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll index f07afaf1b207f..bc20c59c3943b 100644 --- a/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll +++ b/llvm/test/Transforms/LoopUnroll/unroll-and-peel-last-iteration.ll @@ -74,41 +74,96 @@ exit: ; Test case for https://github.com/llvm/llvm-project/issues/142895. define i32 @pr142895_exit_value_is_arg(i32 %arg) { +; CHECK-LABEL: define i32 @pr142895_exit_value_is_arg( +; CHECK-SAME: i32 [[ARG:%.*]]) { +; CHECK-NEXT: [[ENTRY:.*]]: +; CHECK-NEXT: br label %[[LOOP:.*]] +; CHECK: [[LOOP]]: +; CHECK-NEXT: [[INDVAR:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[LOOP]] ] +; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[INDVAR]], 1 +; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 32 +; CHECK-NEXT: br i1 [[EXITCOND]], label %[[LOOP]], label %[[EXIT_PEEL_BEGIN:.*]], !llvm.loop [[LOOP2:![0-9]+]] +; CHECK: [[EXIT_PEEL_BEGIN]]: +; CHECK-NEXT: [[TMP0:%.*]] = phi i32 [ [[INC]], %[[LOOP]] ] +; CHECK-NEXT: br label %[[LOOP_PEEL:.*]] +; CHECK: [[LOOP_PEEL]]: +; CHECK-NEXT: [[CMP1_PEEL:%.*]] = icmp eq i32 [[TMP0]], 32 +; CHECK-NEXT: [[SEL_PEEL:%.*]] = select i1 [[CMP1_PEEL]], i32 0, i32 0 +; CHECK-NEXT: [[SUB_PEEL:%.*]] = sub i32 0, 0 +; CHECK-NEXT: [[XOR_PEEL:%.*]] = xor i32 0, 0 +; CHECK-NEXT: [[INC_PEEL:%.*]] = add i32 [[TMP0]], 1 +; CHECK-NEXT: [[EXITCOND_PEEL:%.*]] = icmp ne i32 [[INC_PEEL]], 33 +; CHECK-NEXT: br i1 [[EXITCOND_PEEL]], label %[[EXIT_PEEL_NEXT:.*]], label %[[EXIT_PEEL_NEXT]] +; CHECK: [[EXIT_PEEL_NEXT]]: +; CHECK-NEXT: br label %[[LOOP_PEEL_NEXT:.*]] +; CHECK: [[LOOP_PEEL_NEXT]]: +; CHECK-NEXT: br label %[[EXIT:.*]] +; CHECK: [[EXIT]]: +; CHECK-NEXT: ret i32 [[ARG]] +; entry: - br label %for.cond.preheader + br label %loop -for.cond.preheader: - %indvar = phi i32 [ 0, %entry ], [ %inc, %for.cond.preheader ] +loop: + %indvar = phi i32 [ 0, %entry ], [ %inc, %loop ] %cmp1 = icmp eq i32 %indvar, 32 %sel = select i1 %cmp1, i32 0, i32 0 %sub = sub i32 0, 0 %xor = xor i32 0, 0 %inc = add i32 %indvar, 1 %exitcond = icmp ne i32 %inc, 33 - br i1 %exitcond, label %for.cond.preheader, label %for.cond.cleanup + br i1 %exitcond, label %loop, label %exit -for.cond.cleanup: - %exit.lcssa = phi i32 [ %arg, %for.cond.preheader ] +exit: + %exit.lcssa = phi i32 [ %arg, %loop ] ret i32 %exit.lcssa } define i32 @pr142895_exit_value_is_inst(i32 %arg) { +; CHECK-LABEL: define i32 @pr142895_exit_value_is_inst( +; CHECK-SAME: i32 [[ARG:%.*]]) { +; CHECK-NEXT: [[ENTRY:.*]]: +; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[ARG]], 7 +; CHECK-NEXT: br label %[[LOOP:.*]] +; CHECK: [[LOOP]]: +; CHECK-NEXT: [[INDVAR:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[LOOP]] ] +; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[INDVAR]], 1 +; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 32 +; CHECK-NEXT: br i1 [[EXITCOND]], label %[[LOOP]], label %[[EXIT_PEEL_BEGIN:.*]], !llvm.loop [[LOOP3:![0-9]+]] +; CHECK: [[EXIT_PEEL_BEGIN]]: +; CHECK-NEXT: [[TMP0:%.*]] = phi i32 [ [[INC]], %[[LOOP]] ] +; CHECK-NEXT: br label %[[LOOP_PEEL:.*]] +; CHECK: [[LOOP_PEEL]]: +; CHECK-NEXT: [[CMP1_PEEL:%.*]] = icmp eq i32 [[TMP0]], 32 +; CHECK-NEXT: [[SEL_PEEL:%.*]] = select i1 [[CMP1_PEEL]], i32 0, i32 0 +; CHECK-NEXT: [[SUB_PEEL:%.*]] = sub i32 0, 0 +; CHECK-NEXT: [[XOR_PEEL:%.*]] = xor i32 0, 0 +; CHECK-NEXT: [[INC_PEEL:%.*]] = add i32 [[TMP0]], 1 +; CHECK-NEXT: [[EXITCOND_PEEL:%.*]] = icmp ne i32 [[INC_PEEL]], 33 +; CHECK-NEXT: br i1 [[EXITCOND_PEEL]], label %[[EXIT_PEEL_NEXT:.*]], label %[[EXIT_PEEL_NEXT]] +; CHECK: [[EXIT_PEEL_NEXT]]: +; CHECK-NEXT: br label %[[LOOP_PEEL_NEXT:.*]] +; CHECK: [[LOOP_PEEL_NEXT]]: +; CHECK-NEXT: br label %[[EXIT:.*]] +; CHECK: [[EXIT]]: +; CHECK-NEXT: ret i32 [[MUL]] +; entry: %mul = mul i32 %arg, 7 - br label %for.cond.preheader + br label %loop -for.cond.preheader: - %indvar = phi i32 [ 0, %entry ], [ %inc, %for.cond.preheader ] +loop: + %indvar = phi i32 [ 0, %entry ], [ %inc, %loop ] %cmp1 = icmp eq i32 %indvar, 32 %sel = select i1 %cmp1, i32 0, i32 0 %sub = sub i32 0, 0 %xor = xor i32 0, 0 %inc = add i32 %indvar, 1 %exitcond = icmp ne i32 %inc, 33 - br i1 %exitcond, label %for.cond.preheader, label %for.cond.cleanup + br i1 %exitcond, label %loop, label %exit -for.cond.cleanup: - %exit.lcssa = phi i32 [ %mul, %for.cond.preheader ] +exit: + %exit.lcssa = phi i32 [ %mul, %loop ] ret i32 %exit.lcssa } @@ -116,4 +171,6 @@ declare void @foo(i32) ;. ; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]]} ; CHECK: [[META1]] = !{!"llvm.loop.peeled.count", i32 1} +; CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[META1]]} +; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]]} ;.