[llvm] r330397 - Revert "This pass, fixing an erratum in some LEON 2 processors..."

[Daniel Cederman via llvm-commits]

Author: dcederman
Date: Fri Apr 20 00:53:27 2018
New Revision: 330397

URL: http://llvm.org/viewvc/llvm-project?rev=330397&view=rev
Log:
Revert "This pass, fixing an erratum in some LEON 2 processors..."

Summary:
Reading Atmel's AT697E errata document this does not seem like a valid
workaround. While the text only mentions SDIV, it says that the ICC flags
can be wrong, and those are only generated by SDIVcc. Verification on
hardware shows that simply replacing SDIV with SDIVcc does not avoid
the bug with negative operands.

This reverts r283727.

Reviewers: lero_chris, jyknight

Reviewed By: jyknight

Subscribers: fedor.sergeev, jrtc27, llvm-commits

Differential Revision: https://reviews.llvm.org/D45813

Removed:
    llvm/trunk/test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll
Modified:
    llvm/trunk/lib/Target/Sparc/LeonFeatures.td
    llvm/trunk/lib/Target/Sparc/Sparc.td
    llvm/trunk/lib/Target/Sparc/SparcISelDAGToDAG.cpp
    llvm/trunk/lib/Target/Sparc/SparcSubtarget.cpp
    llvm/trunk/lib/Target/Sparc/SparcSubtarget.h

Modified: llvm/trunk/lib/Target/Sparc/LeonFeatures.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/LeonFeatures.td?rev=330397&r1=330396&r2=330397&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/LeonFeatures.td (original)
+++ llvm/trunk/lib/Target/Sparc/LeonFeatures.td Fri Apr 20 00:53:27 2018
@@ -37,14 +37,6 @@ def LeonCASA : SubtargetFeature<
   "Enable CASA instruction for LEON3 and LEON4 processors"
 >;
 
-
-def ReplaceSDIV : SubtargetFeature<
-  "replacesdiv",
-  "PerformSDIVReplace",
-  "true",
-  "AT697E erratum fix: Do not emit SDIV, emit SDIVCC instead"
->;
-          
 def InsertNOPLoad: SubtargetFeature<
   "insertnopload",
   "InsertNOPLoad",

Modified: llvm/trunk/lib/Target/Sparc/Sparc.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/Sparc.td?rev=330397&r1=330396&r2=330397&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/Sparc.td (original)
+++ llvm/trunk/lib/Target/Sparc/Sparc.td Fri Apr 20 00:53:27 2018
@@ -130,7 +130,7 @@ def : Processor<"leon2", LEON2Itinerarie
 // LEON 2 FT (AT697E)
 // TO DO: Place-holder: Processor specific features will be added *very* soon here.
 def : Processor<"at697e", LEON2Itineraries,
-                [FeatureLeon, ReplaceSDIV, InsertNOPLoad]>;
+                [FeatureLeon, InsertNOPLoad]>;
 
 // LEON 2 FT (AT697F)
 // TO DO: Place-holder: Processor specific features will be added *very* soon here.

Modified: llvm/trunk/lib/Target/Sparc/SparcISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/SparcISelDAGToDAG.cpp?rev=330397&r1=330396&r2=330397&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/SparcISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/Sparc/SparcISelDAGToDAG.cpp Fri Apr 20 00:53:27 2018
@@ -362,12 +362,6 @@ void SparcDAGToDAGISel::Select(SDNode *N
 
     // FIXME: Handle div by immediate.
     unsigned Opcode = N->getOpcode() == ISD::SDIV ? SP::SDIVrr : SP::UDIVrr;
-    // SDIV is a hardware erratum on some LEON2 processors. Replace it with SDIVcc here.
-    if (((SparcTargetMachine&)TM).getSubtargetImpl()->performSDIVReplace()
-        &&
-        Opcode == SP::SDIVrr) {
-      Opcode = SP::SDIVCCrr;
-    }
     CurDAG->SelectNodeTo(N, Opcode, MVT::i32, DivLHS, DivRHS, TopPart);
     return;
   }

Modified: llvm/trunk/lib/Target/Sparc/SparcSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/SparcSubtarget.cpp?rev=330397&r1=330396&r2=330397&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/SparcSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/Sparc/SparcSubtarget.cpp Fri Apr 20 00:53:27 2018
@@ -44,7 +44,6 @@ SparcSubtarget &SparcSubtarget::initiali
   // Leon features
   HasLeonCasa = false;
   HasUmacSmac = false;
-  PerformSDIVReplace = false;
   InsertNOPLoad = false;
   FixAllFDIVSQRT = false;
   DetectRoundChange = false;

Modified: llvm/trunk/lib/Target/Sparc/SparcSubtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/SparcSubtarget.h?rev=330397&r1=330396&r2=330397&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/SparcSubtarget.h (original)
+++ llvm/trunk/lib/Target/Sparc/SparcSubtarget.h Fri Apr 20 00:53:27 2018
@@ -50,7 +50,6 @@ class SparcSubtarget : public SparcGenSu
   bool InsertNOPLoad;
   bool FixAllFDIVSQRT;
   bool DetectRoundChange;
-  bool PerformSDIVReplace;
 
   SparcInstrInfo InstrInfo;
   SparcTargetLowering TLInfo;
@@ -92,7 +91,6 @@ public:
 
   // Leon options
   bool hasUmacSmac() const { return HasUmacSmac; }
-  bool performSDIVReplace() const { return PerformSDIVReplace; }
   bool hasLeonCasa() const { return HasLeonCasa; }
   bool insertNOPLoad() const { return InsertNOPLoad; }
   bool fixAllFDIVSQRT() const { return FixAllFDIVSQRT; }

Removed: llvm/trunk/test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll?rev=330396&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll (original)
+++ llvm/trunk/test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll (removed)
@@ -1,11 +0,0 @@
-; RUN: llc %s -O0 -march=sparc -o - | FileCheck %s -check-prefix=NO_REPLACE_SDIV
-; RUN: llc %s -O0 -march=sparc -mcpu=at697e -o - | FileCheck %s -check-prefix=REPLACE_SDIV
-
-; REPLACE_SDIV: sdivcc %o0, %o1, %o0
-; NO_REPLACE_SDIV: sdiv %o0, %o1, %o0
-
-define i32 @lbr59(i32 %a, i32 %b)
-{
-  %r = sdiv i32 %a, %b
-  ret i32 %r 
-}