From 8eb3f6d6a0cca2ddf7ebf40e7fae9b0d3963ab6e Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Fri, 10 Oct 2014 17:06:20 +0000 Subject: [PATCH] [MiSched] Fix a logic error in tryPressure() Fixes a logic error in the MachineScheduler found by Steve Montgomery (and confirmed by Andy). This has gone unfixed for months because the fix has been found to introduce some small performance regressions. However, Andy has recommended that, at this point, we fix this to avoid further dependence on the incorrect behavior (and then follow-up separately on any regressions), and I agree. Fixes PR18883. llvm-svn: 219512 --- lib/CodeGen/MachineScheduler.cpp | 4 ++-- test/CodeGen/X86/misched-matmul.ll | 2 +- test/CodeGen/X86/ragreedy-last-chance-recoloring.ll | 6 ++++-- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp index 7e3c33bb9fb..b140fc6d7e9 100644 --- a/lib/CodeGen/MachineScheduler.cpp +++ b/lib/CodeGen/MachineScheduler.cpp @@ -2495,8 +2495,8 @@ static bool tryPressure(const PressureChange &TryP, } // If one candidate decreases and the other increases, go with it. // Invalid candidates have UnitInc==0. - if (tryLess(TryP.getUnitInc() < 0, CandP.getUnitInc() < 0, TryCand, Cand, - Reason)) { + if (tryGreater(TryP.getUnitInc() < 0, CandP.getUnitInc() < 0, TryCand, Cand, + Reason)) { return true; } // If the candidates are decreasing pressure, reverse priority. diff --git a/test/CodeGen/X86/misched-matmul.ll b/test/CodeGen/X86/misched-matmul.ll index 3ea6512258d..5454b7cf780 100644 --- a/test/CodeGen/X86/misched-matmul.ll +++ b/test/CodeGen/X86/misched-matmul.ll @@ -10,7 +10,7 @@ ; more complex cases. ; ; CHECK: @wrap_mul4 -; CHECK: 22 regalloc - Number of spills inserted +; CHECK: 23 regalloc - Number of spills inserted define void @wrap_mul4(double* nocapture %Out, [4 x double]* nocapture %A, [4 x double]* nocapture %B) #0 { entry: diff --git a/test/CodeGen/X86/ragreedy-last-chance-recoloring.ll b/test/CodeGen/X86/ragreedy-last-chance-recoloring.ll index d8e45727b9d..49d58f437c2 100644 --- a/test/CodeGen/X86/ragreedy-last-chance-recoloring.ll +++ b/test/CodeGen/X86/ragreedy-last-chance-recoloring.ll @@ -2,10 +2,12 @@ ; Without the last chance recoloring, this test fails with: ; "ran out of registers". -; RUN: not llc -regalloc=greedy -relocation-model=pic -lcr-max-depth=0 < %s 2>&1 | FileCheck %s --check-prefix=CHECK-DEPTH +; NOTE: With the fix to PR18883, we don't actually run out of registers here +; any more, and so those checks are disabled. This test remains only for general coverage. +; XXX: not llc -regalloc=greedy -relocation-model=pic -lcr-max-depth=0 < %s 2>&1 | FileCheck %s --check-prefix=CHECK-DEPTH ; Test whether failure due to cutoff for depth is reported -; RUN: not llc -regalloc=greedy -relocation-model=pic -lcr-max-interf=1 < %s 2>&1 | FileCheck %s --check-prefix=CHECK-INTERF +; XXX: not llc -regalloc=greedy -relocation-model=pic -lcr-max-interf=1 < %s 2>&1 | FileCheck %s --check-prefix=CHECK-INTERF ; Test whether failure due to cutoff for interference is reported ; RUN: llc -regalloc=greedy -relocation-model=pic -lcr-max-interf=1 -lcr-max-depth=0 -exhaustive-register-search < %s > %t 2>&1