Don't use register classes larger than TLI->getRegClassFor(VT).

In Thumb mode we cannot handle GPR virtual registers, even though some
instructions can. When isel is lowering a CopyFromReg, it should limit
itself to subclasses of getRegClassFor(VT).

<rdar://problem/9624323>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133210 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index e439347228fb8df5a3f95f890e33170a983f686b..2a65d65f4fc5728a7a7cd6adff5a13c7239b1603 100644 (file)
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -76,6 +76,12 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
   // the CopyToReg'd destination register instead of creating a new vreg.
   bool MatchReg = true;
   const TargetRegisterClass *UseRC = NULL;
+  EVT VT = Node->getValueType(ResNo);
+
+  // Stick to the preferred register classes for legal types.
+  if (TLI->isTypeLegal(VT))
+    UseRC = TLI->getRegClassFor(VT);
+
   if (!IsClone && !IsCloned)
     for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
          UI != E; ++UI) {
@@ -121,10 +127,9 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
         break;
     }
 
-  EVT VT = Node->getValueType(ResNo);
   const TargetRegisterClass *SrcRC = 0, *DstRC = 0;
   SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT);
-  
+
   // Figure out the register class to create for the destreg.
   if (VRBase) {
     DstRC = MRI->getRegClass(VRBase);

diff --git a/test/CodeGen/Thumb/2011-06-16-NoGPRs.ll b/test/CodeGen/Thumb/2011-06-16-NoGPRs.ll
new file mode 100644 (file)
index 0000000..d39a760
--- /dev/null
+++ b/test/CodeGen/Thumb/2011-06-16-NoGPRs.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s
+;
+; This test would crash because isel creates a GPR register for the return
+; value from f1. The register is only used by tBLXr_r9 which accepts a full GPR
+; register, but we cannot have live GPRs in thumb mode because we don't know how
+; to spill them.
+;
+; <rdar://problem/9624323>
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
+target triple = "thumbv6-apple-darwin10"
+
+%0 = type opaque
+
+declare i8* (i8*, i8*, ...)* @f1(i8*, i8*) optsize
+declare i8* @f2(i8*, i8*, ...)
+
+define internal void @f(i8* %self, i8* %_cmd, %0* %inObjects, %0* %inIndexes) optsize ssp {
+entry:
+  %call14 = tail call i8* (i8*, i8*, ...)* (i8*, i8*)* @f1(i8* undef, i8* %_cmd) optsize
+  %0 = bitcast i8* (i8*, i8*, ...)* %call14 to void (i8*, i8*, %0*, %0*)*
+  tail call void %0(i8* %self, i8* %_cmd, %0* %inObjects, %0* %inIndexes) optsize
+  tail call void bitcast (i8* (i8*, i8*, ...)* @f2 to void (i8*, i8*, i32, %0*, %0*)*)(i8* %self, i8* undef, i32 2, %0* %inIndexes, %0* undef) optsize
+  ret void
+}