From 560532051b20cfc1a9bc38b8435f670b56092b04 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Fri, 27 May 2011 18:02:04 +0000
Subject: [PATCH] Fix a silly mistake (which trips over an assertion) in
 r132099.  rdar://9515076

llvm-svn: 132194
---
 lib/Target/ARM/ARMFastISel.cpp       |  2 ++
 lib/Transforms/Scalar/LICM.cpp       | 15 ++++++---------
 test/CodeGen/ARM/fast-isel-crash2.ll |  9 +++++++++
 3 files changed, 17 insertions(+), 9 deletions(-)
 create mode 100644 test/CodeGen/ARM/fast-isel-crash2.ll

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 2d2ac670b01..fc0b8d23c71 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -1981,6 +1981,8 @@ bool ARMFastISel::SelectIntCast(const Instruction *I) {
   unsigned Opc;
   bool isZext = isa<ZExtInst>(I);
   bool isBoolZext = false;
+  if (!SrcVT.isSimple())
+    return false;
   switch (SrcVT.getSimpleVT().SimpleTy) {
   default: return false;
   case MVT::i16:
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index d42d4ff837b..935cd5d1ee4 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -372,7 +372,11 @@ bool LICM::canSinkOrHoistInst(Instruction &I) {
     return !pointerInvalidatedByLoop(LI->getOperand(0), Size,
                                      LI->getMetadata(LLVMContext::MD_tbaa));
   } else if (CallInst *CI = dyn_cast<CallInst>(&I)) {
-    // Handle obvious cases efficiently.
+    // Don't sink or hoist dbg info; it's legal, but not useful.
+    if (isa<DbgInfoIntrinsic>(I))
+      return false;
+
+    // Handle simple cases by querying alias analysis.
     AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI);
     if (Behavior == AliasAnalysis::DoesNotAccessMemory)
       return true;
@@ -522,14 +526,7 @@ void LICM::sink(Instruction &I) {
       SSA.AddAvailableValue(ExitBlock, New);
   }
   
-  // If the instruction doesn't dominate any exit blocks, it must be dead.
-  if (NumInserted == 0) {
-    CurAST->deleteValue(&I);
-    if (!I.use_empty())
-      I.replaceAllUsesWith(UndefValue::get(I.getType()));
-    I.eraseFromParent();
-    return;
-  }
+  assert(NumInserted && "We shouldn't see dead instructions here!");
   
   // Next, rewrite uses of the instruction, inserting PHI nodes as needed.
   for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE; ) {
diff --git a/test/CodeGen/ARM/fast-isel-crash2.ll b/test/CodeGen/ARM/fast-isel-crash2.ll
new file mode 100644
index 00000000000..273e67e7e4b
--- /dev/null
+++ b/test/CodeGen/ARM/fast-isel-crash2.ll
@@ -0,0 +1,9 @@
+; RUN: llc < %s -O0 -mtriple=thumbv7-apple-darwin
+; rdar://9515076
+; (Make sure this doesn't crash.)
+
+define i32 @test(i32 %i) {
+  %t = trunc i32 %1 to i4
+  %r = sext i4 %t to i32
+  ret i32 %r
+}