[IPRA] Don't rely on non-exact function definitions

If a function definition is not exact, then the linker could select a
differently-compiled version of it, which could use different registers.

https://reviews.llvm.org/D64909

llvm-svn: 366557

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp b/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
index fc4be82d215..0205e619374 100644
--- a/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
+++ b/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
@@ -130,7 +130,11 @@ bool RegUsageInfoPropagation::runOnMachineFunction(MachineFunction &MF) {
       };
 
       if (const Function *F = findCalledFunction(M, MI)) {
-        UpdateRegMask(*F);
+        if (F->isDefinitionExact()) {
+          UpdateRegMask(*F);
+        } else {
+          LLVM_DEBUG(dbgs() << "Function definition is not exact\n");
+        }
       } else {
         LLVM_DEBUG(dbgs() << "Failed to find call target function\n");
       }