[llvm] r334586 - [TableGen] Emit a fatal error on inconsistencies in resource units vs cycles.

[Clement Courbet via llvm-commits]

Author: courbet
Date: Wed Jun 13 02:41:49 2018
New Revision: 334586

URL: http://llvm.org/viewvc/llvm-project?rev=334586&view=rev
Log:
[TableGen] Emit a fatal error on inconsistencies in resource units vs cycles.

Summary:
For targets I'm not familiar with, I've automatically made the "default to 1 for each resource" behaviour explicit in the td files.
For more obvious cases, I've ventured a fix.

Some notes:
 - Exynos is especially fishy.
 - AArch64SchedThunderX2T99.td had some truncated entries. If I understand correctly, the person who wrote that interpreted the ResourceCycle as a range. I made the decision to use the upper/lower bound for consistency with the 'Latency' value. I'm sure there is a better choice.
 - The change to X86ScheduleBtVer2.td is an NFC, it just makes values more explicit.

Also see PR37310.

Reviewers: RKSimon, craig.topper, javed.absar

Subscribers: kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D46356

Modified:
    llvm/trunk/include/llvm/Target/TargetSchedule.td
    llvm/trunk/lib/Target/AArch64/AArch64SchedThunderX2T99.td
    llvm/trunk/utils/TableGen/SubtargetEmitter.cpp

Modified: llvm/trunk/include/llvm/Target/TargetSchedule.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetSchedule.td?rev=334586&r1=334585&r2=334586&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetSchedule.td (original)
+++ llvm/trunk/include/llvm/Target/TargetSchedule.td Wed Jun 13 02:41:49 2018
@@ -281,10 +281,9 @@ class ProcWriteResources<list<ProcResour
 // ProcResources indicates the set of resources consumed by the write.
 // Optionally, ResourceCycles indicates the number of cycles the
 // resource is consumed. Each ResourceCycles item is paired with the
-// ProcResource item at the same position in its list. Since
-// ResourceCycles are rarely specialized, the list may be
-// incomplete. By default, resources are consumed for a single cycle,
-// regardless of latency, which models a fully pipelined processing
+// ProcResource item at the same position in its list. ResourceCycles
+// can be `[]`: in that case, all resources are consumed for a single
+// cycle, regardless of latency, which models a fully pipelined processing
 // unit. A value of 0 for ResourceCycles means that the resource must
 // be available but is not consumed, which is only relevant for
 // unbuffered resources.

Modified: llvm/trunk/lib/Target/AArch64/AArch64SchedThunderX2T99.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64SchedThunderX2T99.td?rev=334586&r1=334585&r2=334586&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64SchedThunderX2T99.td (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64SchedThunderX2T99.td Wed Jun 13 02:41:49 2018
@@ -416,7 +416,7 @@ def : InstRW<[THX2T99Write_1Cyc_I2],
 // Address generation
 def : WriteRes<WriteI,       [THX2T99I012]> {
   let Latency = 1;
-  let ResourceCycles = [1, 3];
+  let ResourceCycles = [1];
   let NumMicroOps = 2;
 }
 
@@ -438,7 +438,7 @@ def : InstRW<[WriteI], (instrs COPY)>;
 // ALU, extend and/or shift
 def : WriteRes<WriteISReg,   [THX2T99I012]> {
   let Latency = 2;
-  let ResourceCycles = [2, 3];
+  let ResourceCycles = [2];
   let NumMicroOps = 2;
 }
 
@@ -457,7 +457,7 @@ def : InstRW<[WriteISReg],
 
 def : WriteRes<WriteIEReg,   [THX2T99I012]> {
   let Latency = 1;
-  let ResourceCycles = [1, 3];
+  let ResourceCycles = [1];
   let NumMicroOps = 2;
 }
 
@@ -500,14 +500,14 @@ def : WriteRes<WriteIS,      [THX2T99I01
 // Latency range of 13-23/13-39.
 def : WriteRes<WriteID32,    [THX2T99I1]> {
   let Latency = 39;
-  let ResourceCycles = [13, 39];
+  let ResourceCycles = [39];
   let NumMicroOps = 4;
 }
 
 // Divide, X-form
 def : WriteRes<WriteID64,    [THX2T99I1]> {
   let Latency = 23;
-  let ResourceCycles = [13, 23];
+  let ResourceCycles = [23];
   let NumMicroOps = 4;
 }
 
@@ -1252,7 +1252,7 @@ def : InstRW<[THX2T99Write_5Cyc_F01], (i
 def : WriteRes<WriteV, [THX2T99F01]> {
   let Latency = 7;
   let NumMicroOps = 4;
-  let ResourceCycles = [4, 23];
+  let ResourceCycles = [4];
 }
 
 // ASIMD arith, reduce, 4H/4S

Modified: llvm/trunk/utils/TableGen/SubtargetEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/SubtargetEmitter.cpp?rev=334586&r1=334585&r2=334586&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/SubtargetEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/SubtargetEmitter.cpp Wed Jun 13 02:41:49 2018
@@ -941,8 +941,7 @@ Record *SubtargetEmitter::FindReadAdvanc
 void SubtargetEmitter::ExpandProcResources(RecVec &PRVec,
                                            std::vector<int64_t> &Cycles,
                                            const CodeGenProcModel &PM) {
-  // Default to 1 resource cycle.
-  Cycles.resize(PRVec.size(), 1);
+  assert(PRVec.size() == Cycles.size() && "failed precondition");
   for (unsigned i = 0, e = PRVec.size(); i != e; ++i) {
     Record *PRDef = PRVec[i];
     RecVec SubResources;
@@ -1111,6 +1110,21 @@ void SubtargetEmitter::GenSchedClassTabl
         std::vector<int64_t> Cycles =
           WriteRes->getValueAsListOfInts("ResourceCycles");
 
+        if (Cycles.empty()) {
+          // If ResourceCycles is not provided, default to one cycle per
+          // resource.
+          Cycles.resize(PRVec.size(), 1);
+        } else if (Cycles.size() != PRVec.size()) {
+          // If ResourceCycles is provided, check consistency.
+          PrintFatalError(
+              WriteRes->getLoc(),
+              Twine("Inconsistent resource cycles: !size(ResourceCycles) != "
+                    "!size(ProcResources): ")
+                  .concat(Twine(PRVec.size()))
+                  .concat(" vs ")
+                  .concat(Twine(Cycles.size())));
+        }
+
         ExpandProcResources(PRVec, Cycles, ProcModel);
 
         for (unsigned PRIdx = 0, PREnd = PRVec.size();