[PATCH] D45070: [NVPTX] Enable StructuredCFG for NVPTX

[Tim Shen via Phabricator via llvm-commits]

timshen created this revision.
timshen added a reviewer: jlebar.
Herald added subscribers: hiraditya, sanjoy, jholewinski.

Make NVPTX require structured CFG. Added a temporary flag to
"roll back" the behavior for easy deployment.

Combined with https://reviews.llvm.org/D45008, this fixes several internal Nvidia GPU test
failures that we suspect to be ptxas miscompiles (PR27738).


https://reviews.llvm.org/D45070

Files:
  llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp


Index: llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
===================================================================
--- llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -44,6 +44,14 @@
                                cl::desc("Disable load/store vectorizer"),
                                cl::init(false), cl::Hidden);
 
+// TODO: Remove this flag when we are confident with no regressions.
+static cl::opt<bool> DisableRequireStructuredCFG(
+    "disable-nvptx-require-structured-cfg",
+    cl::desc("Transitional flag to turn off NVPTX's requirement on preserving "
+             "structured CFG. The requirement should be disabled only when "
+             "unexpected regressions happen."),
+    cl::init(false), cl::Hidden);
+
 namespace llvm {
 
 void initializeNVVMIntrRangePass(PassRegistry&);
@@ -108,6 +116,8 @@
     drvInterface = NVPTX::NVCL;
   else
     drvInterface = NVPTX::CUDA;
+  if (!DisableRequireStructuredCFG)
+    setRequiresStructuredCFG(true);
   initAsmInfo();
 }
 


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