R600/SI: Fix verifier error caused by SIAnnotateControlFlow

This pass will always try to insert llvm.SI.ifbreak intrinsics
in the same block that its conditional value is computed in.  This is
a problem when conditions for breaks or continue are computed outside
of the loop, because the llvm.SI.ifbreak intrinsic ends up being inserted
outside of the loop.

This patch fixes this problem by inserting the llvm.SI.ifbreak
intrinsics in the loop header when the condition is computed outside
the loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234891 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/R600/SIAnnotateControlFlow.cpp b/lib/Target/R600/SIAnnotateControlFlow.cpp
index 79f6532f1d7bb0a7015bcb25cadc8b49df5ab45c..d39ab3f185095ec55c3362de57f6fb7ba81283a0 100644 (file)
--- a/lib/Target/R600/SIAnnotateControlFlow.cpp
+++ b/lib/Target/R600/SIAnnotateControlFlow.cpp
@@ -83,7 +83,7 @@ class SIAnnotateControlFlow : public FunctionPass {
 
   void insertElse(BranchInst *Term);
 
-  Value *handleLoopCondition(Value *Cond, PHINode *Broken);
+  Value *handleLoopCondition(Value *Cond, PHINode *Broken, llvm::Loop *L);
 
   void handleLoop(BranchInst *Term);
 
@@ -207,7 +207,8 @@ void SIAnnotateControlFlow::insertElse(BranchInst *Term) {
 }
 
 /// \brief Recursively handle the condition leading to a loop
-Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken) {
+Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken,
+                                                  llvm::Loop *L) {
   if (PHINode *Phi = dyn_cast<PHINode>(Cond)) {
     BasicBlock *Parent = Phi->getParent();
     PHINode *NewPhi = PHINode::Create(Int64, 0, "", &Parent->front());
@@ -223,7 +224,7 @@ Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken)
       }
 
       Phi->setIncomingValue(i, BoolFalse);
-      Value *PhiArg = handleLoopCondition(Incoming, Broken);
+      Value *PhiArg = handleLoopCondition(Incoming, Broken, L);
       NewPhi->addIncoming(PhiArg, From);
     }
 
@@ -253,7 +254,12 @@ Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken)
 
   } else if (Instruction *Inst = dyn_cast<Instruction>(Cond)) {
     BasicBlock *Parent = Inst->getParent();
-    TerminatorInst *Insert = Parent->getTerminator();
+    Instruction *Insert;
+    if (L->contains(Inst)) {
+      Insert = Parent->getTerminator();
+    } else {
+      Insert = L->getHeader()->getFirstNonPHIOrDbgOrLifetime();
+    }
     Value *Args[] = { Cond, Broken };
     return CallInst::Create(IfBreak, Args, "", Insert);
 
@@ -265,14 +271,15 @@ Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken)
 
 /// \brief Handle a back edge (loop)
 void SIAnnotateControlFlow::handleLoop(BranchInst *Term) {
+  BasicBlock *BB = Term->getParent();
+  llvm::Loop *L = LI->getLoopFor(BB);
   BasicBlock *Target = Term->getSuccessor(1);
   PHINode *Broken = PHINode::Create(Int64, 0, "", &Target->front());
 
   Value *Cond = Term->getCondition();
   Term->setCondition(BoolTrue);
-  Value *Arg = handleLoopCondition(Cond, Broken);
+  Value *Arg = handleLoopCondition(Cond, Broken, L);
 
-  BasicBlock *BB = Term->getParent();
   for (pred_iterator PI = pred_begin(Target), PE = pred_end(Target);
        PI != PE; ++PI) {
 

diff --git a/test/CodeGen/R600/si-annotate-cf.ll b/test/CodeGen/R600/si-annotate-cf.ll
new file mode 100644 (file)
index 0000000..3f30988
--- /dev/null
+++ b/test/CodeGen/R600/si-annotate-cf.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s -march=amdgcn -mcpu=verde -verify-machineinstrs | FileCheck --check-prefix=SI --check-prefix=FUNC %s
+; RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs | FileCheck --check-prefix=SI --check-prefix=FUNC %s
+
+; FUNC-LABEL: {{^}}break_inserted_outside_of_loop:
+
+; SI: [[LOOP_LABEL:[A-Z0-9]+]]:
+; Lowered break instructin:
+; SI: s_or_b64
+; Lowered Loop instruction:
+; SI: s_andn2_b64
+; s_cbranch_execnz [[LOOP_LABEL]]
+; SI: s_endpgm
+define void @break_inserted_outside_of_loop(i32 addrspace(1)* %out, i32 %a, i32 %b) {
+main_body:
+  %0 = and i32 %a, %b
+  %1 = trunc i32 %0 to i1
+  br label %ENDIF
+
+ENDLOOP:
+  store i32 0, i32 addrspace(1)* %out
+  ret void
+
+ENDIF:
+  br i1 %1, label %ENDLOOP, label %ENDIF
+}