[PATCH] D45813: Revert "This pass, fixing an erratum in some LEON 2 processors..."

[Daniel Cederman via Phabricator via llvm-commits]

dcederman created this revision.
dcederman added reviewers: lero_chris, jyknight.
Herald added subscribers: llvm-commits, jrtc27, fedor.sergeev.

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.


Repository:
  rL LLVM

https://reviews.llvm.org/D45813

Files:
  lib/Target/Sparc/LeonFeatures.td
  lib/Target/Sparc/Sparc.td
  lib/Target/Sparc/SparcISelDAGToDAG.cpp
  lib/Target/Sparc/SparcSubtarget.cpp
  lib/Target/Sparc/SparcSubtarget.h
  test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll


Index: test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll
===================================================================
--- test/CodeGen/SPARC/LeonReplaceSDIVPassUT.ll
+++ /dev/null
@@ -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 
-}
Index: lib/Target/Sparc/SparcSubtarget.h
===================================================================
--- lib/Target/Sparc/SparcSubtarget.h
+++ lib/Target/Sparc/SparcSubtarget.h
@@ -50,7 +50,6 @@
   bool InsertNOPLoad;
   bool FixAllFDIVSQRT;
   bool DetectRoundChange;
-  bool PerformSDIVReplace;
 
   SparcInstrInfo InstrInfo;
   SparcTargetLowering TLInfo;
@@ -92,7 +91,6 @@
 
   // 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; }
Index: lib/Target/Sparc/SparcSubtarget.cpp
===================================================================
--- lib/Target/Sparc/SparcSubtarget.cpp
+++ lib/Target/Sparc/SparcSubtarget.cpp
@@ -44,7 +44,6 @@
   // Leon features
   HasLeonCasa = false;
   HasUmacSmac = false;
-  PerformSDIVReplace = false;
   InsertNOPLoad = false;
   FixAllFDIVSQRT = false;
   DetectRoundChange = false;
Index: lib/Target/Sparc/SparcISelDAGToDAG.cpp
===================================================================
--- lib/Target/Sparc/SparcISelDAGToDAG.cpp
+++ lib/Target/Sparc/SparcISelDAGToDAG.cpp
@@ -360,12 +360,6 @@
 
     // 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;
   }
Index: lib/Target/Sparc/Sparc.td
===================================================================
--- lib/Target/Sparc/Sparc.td
+++ lib/Target/Sparc/Sparc.td
@@ -130,7 +130,7 @@
 // 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.
Index: lib/Target/Sparc/LeonFeatures.td
===================================================================
--- lib/Target/Sparc/LeonFeatures.td
+++ lib/Target/Sparc/LeonFeatures.td
@@ -37,14 +37,6 @@
   "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",


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