From 61968286f9a39815040b0d94299c3732834661bf Mon Sep 17 00:00:00 2001 From: Karthika Devi C Date: Mon, 8 Jan 2024 23:18:02 +0530 Subject: [PATCH] [polly][ScheduleOptimizer] Reland Fix long compile time(hang) reported in polly (#77280) There is no upper cap set on current Schedule Optimizer to compute schedule. In some cases a very long compile time taken to compute the schedule resulting in hang kind of behavior. This patch introduces a flag 'polly-schedule-computeout' to pass the capwhich is initialized to 300000. This patch handles the compute out cases by bailing out and exiting gracefully. Fixed the test that failed in previous commit. Fixes #69090 --- polly/lib/Transform/ScheduleOptimizer.cpp | 25 +++++ .../ScheduleOptimizer/schedule_computeout.ll | 99 +++++++++++++++++++ 2 files changed, 124 insertions(+) create mode 100644 polly/test/ScheduleOptimizer/schedule_computeout.ll diff --git a/polly/lib/Transform/ScheduleOptimizer.cpp b/polly/lib/Transform/ScheduleOptimizer.cpp index 35a0a4def040..8ee2b66339ad 100644 --- a/polly/lib/Transform/ScheduleOptimizer.cpp +++ b/polly/lib/Transform/ScheduleOptimizer.cpp @@ -96,6 +96,13 @@ static cl::opt cl::desc("Maximize the band depth (yes/no)"), cl::Hidden, cl::init("yes"), cl::cat(PollyCategory)); +static cl::opt + ScheduleComputeOut("polly-schedule-computeout", + cl::desc("Bound the scheduler by maximal amount" + "of computational steps. "), + cl::Hidden, cl::init(300000), cl::ZeroOrMore, + cl::cat(PollyCategory)); + static cl::opt GreedyFusion("polly-loopfusion-greedy", cl::desc("Aggressively try to fuse everything"), cl::Hidden, @@ -860,7 +867,25 @@ static void runIslScheduleOptimizer( SC = SC.set_proximity(Proximity); SC = SC.set_validity(Validity); SC = SC.set_coincidence(Validity); + + // Save error handling behavior + long MaxOperations = isl_ctx_get_max_operations(Ctx); + isl_ctx_set_max_operations(Ctx, ScheduleComputeOut); Schedule = SC.compute_schedule(); + bool ScheduleQuota = false; + if (isl_ctx_last_error(Ctx) == isl_error_quota) { + isl_ctx_reset_error(Ctx); + LLVM_DEBUG( + dbgs() << "Schedule optimizer calculation exceeds ISL quota\n"); + ScheduleQuota = true; + } + isl_options_set_on_error(Ctx, ISL_ON_ERROR_ABORT); + isl_ctx_reset_operations(Ctx); + isl_ctx_set_max_operations(Ctx, MaxOperations); + + if (ScheduleQuota) + return; + isl_options_set_on_error(Ctx, OnErrorStatus); ScopsRescheduled++; diff --git a/polly/test/ScheduleOptimizer/schedule_computeout.ll b/polly/test/ScheduleOptimizer/schedule_computeout.ll new file mode 100644 index 000000000000..eb59f0e36ac6 --- /dev/null +++ b/polly/test/ScheduleOptimizer/schedule_computeout.ll @@ -0,0 +1,99 @@ +; RUN: opt %loadPolly -S -polly-optree -polly-delicm -polly-opt-isl -polly-schedule-computeout=100000 -debug-only="polly-opt-isl" < %s 2>&1 | FileCheck %s +; REQUIRES: asserts + +; Bailout if the computations of schedule compute exceeds the max scheduling quota. +; Max compute out is initialized to 300000, Here it is set to 100000 for test purpose. + +target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128" +target triple = "aarch64-unknown-linux-gnu" + +@a = dso_local local_unnamed_addr global ptr null, align 8 +@b = dso_local local_unnamed_addr global ptr null, align 8 +@c = dso_local local_unnamed_addr global ptr null, align 8 + +define dso_local void @foo(i32 noundef %I, i32 noundef %J, i32 noundef %K1, i32 noundef %K2, i32 noundef %L1, i32 noundef %L2) local_unnamed_addr { +entry: + %j = alloca i32, align 4 + store volatile i32 0, ptr %j, align 4 + %j.0.j.0.j.0.54 = load volatile i32, ptr %j, align 4 + %cmp55 = icmp slt i32 %j.0.j.0.j.0.54, %J + br i1 %cmp55, label %for.body.lr.ph, label %for.cond.cleanup + +for.body.lr.ph: ; preds = %entry + %0 = load ptr, ptr @a, align 8 + %1 = load ptr, ptr @b, align 8 + %2 = load ptr, ptr %1, align 8 + %cmp352 = icmp slt i32 %L1, %L2 + %cmp750 = icmp slt i32 %K1, %K2 + %3 = sext i32 %K1 to i64 + %4 = sext i32 %L1 to i64 + br label %for.body + +for.cond.cleanup: ; preds = %for.cond.cleanup4, %entry + ret void + +for.body: ; preds = %for.cond.cleanup4, %for.body.lr.ph + br i1 %cmp352, label %for.cond6.preheader.preheader, label %for.cond.cleanup4 + +for.cond6.preheader.preheader: ; preds = %for.body + %wide.trip.count66 = sext i32 %L2 to i64 + br label %for.cond6.preheader + +for.cond6.preheader: ; preds = %for.cond.cleanup8, %for.cond6.preheader.preheader + %indvars.iv61 = phi i64 [ %4, %for.cond6.preheader.preheader ], [ %indvars.iv.next62, %for.cond.cleanup8 ] + br i1 %cmp750, label %for.cond10.preheader.lr.ph, label %for.cond.cleanup8 + +for.cond10.preheader.lr.ph: ; preds = %for.cond6.preheader + %5 = mul nsw i64 %indvars.iv61, 516 + %6 = mul nsw i64 %indvars.iv61, 516 + %wide.trip.count = sext i32 %K2 to i64 + br label %for.cond10.preheader + +for.cond.cleanup4: ; preds = %for.cond.cleanup8, %for.body + %j.0.j.0.j.0.45 = load volatile i32, ptr %j, align 4 + %inc34 = add nsw i32 %j.0.j.0.j.0.45, 1 + store volatile i32 %inc34, ptr %j, align 4 + %j.0.j.0.j.0. = load volatile i32, ptr %j, align 4 + %cmp = icmp slt i32 %j.0.j.0.j.0., %J + br i1 %cmp, label %for.body, label %for.cond.cleanup + +for.cond10.preheader: ; preds = %for.cond.cleanup12, %for.cond10.preheader.lr.ph + %indvars.iv = phi i64 [ %3, %for.cond10.preheader.lr.ph ], [ %indvars.iv.next, %for.cond.cleanup12 ] + %7 = getelementptr float, ptr %0, i64 %indvars.iv + %arrayidx18 = getelementptr float, ptr %7, i64 %5 + %8 = load float, ptr %arrayidx18, align 4 + br label %for.cond14.preheader + +for.cond.cleanup8: ; preds = %for.cond.cleanup12, %for.cond6.preheader + %indvars.iv.next62 = add nsw i64 %indvars.iv61, 1 + %exitcond67.not = icmp eq i64 %indvars.iv.next62, %wide.trip.count66 + br i1 %exitcond67.not, label %for.cond.cleanup4, label %for.cond6.preheader + +for.cond14.preheader: ; preds = %for.cond.cleanup16, %for.cond10.preheader + %m.049 = phi i32 [ -2, %for.cond10.preheader ], [ %inc21, %for.cond.cleanup16 ] + %sum.048 = phi float [ 0.000000e+00, %for.cond10.preheader ], [ %add19, %for.cond.cleanup16 ] + br label %for.body17 + +for.cond.cleanup12: ; preds = %for.cond.cleanup16 + %9 = getelementptr float, ptr %2, i64 %indvars.iv + %arrayidx26 = getelementptr float, ptr %9, i64 %6 + store float %add19, ptr %arrayidx26, align 4 + %indvars.iv.next = add nsw i64 %indvars.iv, 1 + %exitcond60.not = icmp eq i64 %indvars.iv.next, %wide.trip.count + br i1 %exitcond60.not, label %for.cond.cleanup8, label %for.cond10.preheader + +for.cond.cleanup16: ; preds = %for.body17 + %inc21 = add nsw i32 %m.049, 1 + %exitcond56.not = icmp eq i32 %inc21, 3 + br i1 %exitcond56.not, label %for.cond.cleanup12, label %for.cond14.preheader + +for.body17: ; preds = %for.body17, %for.cond14.preheader + %n.047 = phi i32 [ -2, %for.cond14.preheader ], [ %inc, %for.body17 ] + %sum.146 = phi float [ %sum.048, %for.cond14.preheader ], [ %add19, %for.body17 ] + %add19 = fadd float %sum.146, %8 + %inc = add nsw i32 %n.047, 1 + %exitcond.not = icmp eq i32 %inc, 3 + br i1 %exitcond.not, label %for.cond.cleanup16, label %for.body17 +} + +; CHECK: Schedule optimizer calculation exceeds ISL quota