IPRA: Don't assume called function is first call operand

Fixes not finding the called global for AMDGPU
call pseudoinstructions, which prevented IPRA
from doing much.

llvm-svn: 311637

1 files changed, 20 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp b/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
index a39c945..f6d4506 100644
--- a/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
+++ b/llvm/lib/CodeGen/RegUsageInfoPropagate.cpp
@@ -88,6 +88,19 @@ void RegUsageInfoPropagationPass::getAnalysisUsage(AnalysisUsage &AU) const {
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
+// Assumes call instructions have a single reference to a function.
+static const Function *findCalledFunction(const Module &M, MachineInstr &MI) {
+  for (MachineOperand &MO : MI.operands()) {
+    if (MO.isGlobal())
+      return dyn_cast<Function>(MO.getGlobal());
+
+    if (MO.isSymbol())
+      return M.getFunction(MO.getSymbolName());
+  }
+
+  return nullptr;
+}
+
 bool RegUsageInfoPropagationPass::runOnMachineFunction(MachineFunction &MF) {
   const Module *M = MF.getFunction()->getParent();
   PhysicalRegisterUsageInfo *PRUI = &getAnalysis<PhysicalRegisterUsageInfo>();
@@ -118,15 +131,14 @@ bool RegUsageInfoPropagationPass::runOnMachineFunction(MachineFunction &MF) {
         Changed = true;
       };
 
-      MachineOperand &Operand = MI.getOperand(0);
-      if (Operand.isGlobal())
-        UpdateRegMask(cast<Function>(Operand.getGlobal()));
-      else if (Operand.isSymbol())
-        UpdateRegMask(M->getFunction(Operand.getSymbolName()));
+      if (const Function *F = findCalledFunction(*M, MI)) {
+        UpdateRegMask(F);
+      } else {
+        DEBUG(dbgs() << "Failed to find call target function\n");
+      }
 
-      DEBUG(dbgs()
-            << "Call Instruction After Register Usage Info Propagation : \n");
-      DEBUG(dbgs() << MI << "\n");
+      DEBUG(dbgs() << "Call Instruction After Register Usage Info Propagation : "
+            << MI << '\n');
     }
   }