GlobalISel: clear vreg mapping after translating each function

Otherwise we only materialize (shared) constants in the first function they
appear in. This doesn't go well.

llvm-svn: 278351

llvm/include/llvm/CodeGen/GlobalISel/IRTranslator.h

@@ -252,7 +252,7 @@ private:
   // at the proper place. E.g., Entry block or dominator block
   // of each constant depending on how fancy we want to be.
   // * Clear the different maps.
-  void finalize();
+  void finalizeFunction();
 
   /// Get the VReg that represents \p Val.
   /// If such VReg does not exist, it is created.

llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp

@@ -311,7 +311,9 @@ bool IRTranslator::translate(const Constant &C, unsigned Reg) {
 }
 
 
-void IRTranslator::finalize() {
+void IRTranslator::finalizeFunction() {
+  finishPendingPhis();
+
   // Release the memory used by the different maps we
   // needed during the translation.
   ValToVReg.clear();
@@ -362,7 +364,7 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &MF) {
     }
   }
 
-  finishPendingPhis();
+  finalizeFunction();
 
   // Now that the MachineFrameInfo has been configured, no further changes to
   // the reserved registers are possible.

llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll

@@ -397,3 +397,12 @@ define i32 @test_undef() {
 define i8* @test_constant_inttoptr() {
   ret i8* inttoptr(i64 1 to i8*)
 }
+
+  ; This failed purely because the Constant -> VReg map was kept across
+  ; functions, so reuse the "i64 1" from above.
+; CHECK-LABEL: name: test_reused_constant
+; CHECK: [[ONE:%[0-9]+]](64) = G_CONSTANT s64 1
+; CHECK: %x0 = COPY [[ONE]]
+define i64 @test_reused_constant() {
+  ret i64 1
+}