Only emit exit for PTX v8.3+

Author: justinfargnoli

llvm/lib/Target/NVPTX/NVPTXInstrInfo.td

@@ -139,6 +139,8 @@ def hasVote : Predicate<"Subtarget->hasVote()">;
 def hasDouble : Predicate<"Subtarget->hasDouble()">;
 def hasLDG : Predicate<"Subtarget->hasLDG()">;
 def hasLDU : Predicate<"Subtarget->hasLDU()">;
+def hasPTXASUnreachableBug : Predicate<"Subtarget->hasPTXASUnreachableBug()">;
+def noPTXASUnreachableBug : Predicate<"!Subtarget->hasPTXASUnreachableBug()">;
 
 def doF32FTZ : Predicate<"useF32FTZ()">;
 def doNoF32FTZ : Predicate<"!useF32FTZ()">;
@@ -3736,9 +3738,10 @@ def Callseq_End :
             [(callseq_end timm:$amt1, timm:$amt2)]>;
 
 // trap instruction
+def trapinst : NVPTXInst<(outs), (ins), "trap;", [(trap)]>, Requires<[noPTXASUnreachableBug]>;
 // Emit an `exit` as well to convey to ptxas that `trap` exits the CFG.
 // This won't be necessary in a future version of ptxas.
-def trapinst : NVPTXInst<(outs), (ins), "trap; exit;", [(trap)]>;
+def trapinstexit : NVPTXInst<(outs), (ins), "trap; exit;", [(trap)]>, Requires<[hasPTXASUnreachableBug]>;
 // brkpt instruction
 def debugtrapinst : NVPTXInst<(outs), (ins), "brkpt;", [(debugtrap)]>;
 

llvm/lib/Target/NVPTX/NVPTXSubtarget.h

@@ -95,7 +95,7 @@ class NVPTXSubtarget : public NVPTXGenSubtargetInfo {
   bool hasDotInstructions() const {
     return SmVersion >= 61 && PTXVersion >= 50;
   }
-  bool hasPTXASUnreachableBug() const { return PTXVersion <= 83; }
+  bool hasPTXASUnreachableBug() const { return PTXVersion < 83; }
   bool hasCvtaParam() const { return SmVersion >= 70 && PTXVersion >= 77; }
   unsigned int getFullSmVersion() const { return FullSmVersion; }
   unsigned int getSmVersion() const { return getFullSmVersion() / 10; }

llvm/test/CodeGen/NVPTX/unreachable.ll

@@ -1,17 +1,17 @@
 ; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable=false \
-; RUN:     | FileCheck %s  --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
+; RUN:     | FileCheck %s  --check-prefixes=CHECK,CHECK-NOTRAP
 ; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable=false \
-; RUN:     | FileCheck %s  --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
+; RUN:     | FileCheck %s  --check-prefixes=CHECK,CHECK-NOTRAP
 ; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn \
-; RUN:     | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
+; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-NOTRAP
 ; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn \
-; RUN:     | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
+; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-NOTRAP
 ; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn=false \
-; RUN:     | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-TRAP
+; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-TRAP
 ; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn=false \
-; RUN:     | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-TRAP
-; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -mattr=+ptx75 \
-; RUN:     | FileCheck %s  --check-prefixes=CHECK-BUG-FIXED
+; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-TRAP
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -mattr=+ptx83 \
+; RUN:     | FileCheck %s  --check-prefix=CHECK-BUG-FIXED
 ; RUN: %if ptxas && !ptxas-12.0 %{ llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs | %ptxas-verify %}
 ; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs | %ptxas-verify %}
 
@@ -26,21 +26,26 @@ define void @kernel_func() {
   call void @throw()
 ; CHECK-TRAP-NOT: exit;
 ; CHECK-TRAP: trap;
+
 ; CHECK-NOTRAP-NOT: trap;
 ; CHECK: exit;
+
 ; CHECK-BUG-FIXED-NOT: exit;
+; CHECK-BUG-FIXED: trap;
   unreachable
 }
 
 ; CHECK-LABEL: kernel_func_2
 define void @kernel_func_2() {
 ; CHECK: trap; exit;
-; CHECK-BUG-FIXED-NOT: exit;
+; CHECK-BUG-FIXED: trap;
+; CHECK-BUG-FIXED-NOT: trap; exit;
   call void @llvm.trap()
 
 ;; Make sure we avoid emitting two trap instructions.
 ; CHECK-NOT: trap;
 ; CHECK-NOT: exit;
+; CHECK-BUG-FIXED-NOT: trap; 
   unreachable
 }