Fix for PR18396: Assertion: MO->isDead "Cannot fold physreg def".

InlineSpiller::foldMemoryOperand needs to handle undef call operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198679 91177308-0d34-0410-b5e6-96231b3b80d8

Author: atrick

lib/CodeGen/InlineSpiller.cpp

@@ -1098,12 +1098,11 @@ foldMemoryOperand(ArrayRef<std::pair<MachineInstr*, unsigned> > Ops,
         MRI.isReserved(Reg)) {
       continue;
     }
+    // Skip non-Defs, including undef uses and internal reads.
+    if (MO->isUse())
+      continue;
     MIBundleOperands::PhysRegInfo RI =
       MIBundleOperands(FoldMI).analyzePhysReg(Reg, &TRI);
-    if (MO->readsReg()) {
-      assert(RI.Reads && "Cannot fold physreg reader");
-      continue;
-    }
     if (RI.Defines)
       continue;
     // FoldMI does not define this physreg. Remove the LI segment.

test/CodeGen/X86/fold-call-oper.ll

@@ -0,0 +1,48 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+;
+; PR18396: Assertion: MO->isDead "Cannot fold physreg def".
+; InlineSpiller::foldMemoryOperand needs to handle undef call operands.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+@a = external global i32**, align 8
+@b = external global i32, align 4
+
+; Check that the call targets are folded, and we don't crash!
+; CHECK-LABEL: foldCallOper:
+; CHECK: callq *{{.*}}(%rbp)
+; CHECK: callq *{{.*}}(%rbp)
+define void @foldCallOper(i32 (i32*, i32, i32**)* nocapture %p1) #0 {
+entry:
+  %0 = load i32*** @a, align 8
+  br label %for.body.i
+
+for.body.i:                                       ; preds = %for.body.i, %entry
+  %exitcond5.i = icmp eq i32 undef, undef
+  br i1 %exitcond5.i, label %for.body3.lr.ph.i, label %for.body.i
+
+for.body3.lr.ph.i:                                ; preds = %for.body.i
+  %call.i = tail call i32 %p1(i32* undef, i32 0, i32** null)
+  %tobool.i = icmp eq i32 %call.i, 0
+  br label %for.body3.i
+
+for.body3.i:                                      ; preds = %for.inc8.i, %for.body3.lr.ph.i
+  %1 = phi i32* [ undef, %for.body3.lr.ph.i ], [ %.pre.i, %for.inc8.i ]
+  %indvars.iv.i = phi i64 [ 1, %for.body3.lr.ph.i ], [ %phitmp.i, %for.inc8.i ]
+  %call5.i = tail call i32 %p1(i32* %1, i32 0, i32** %0)
+  br i1 %tobool.i, label %for.inc8.i, label %if.then.i
+
+if.then.i:                                        ; preds = %for.body3.i
+  %2 = load i32* %1, align 4
+  store i32 %2, i32* @b, align 4
+  br label %for.inc8.i
+
+for.inc8.i:                                       ; preds = %if.then.i, %for.body3.i
+  %lftr.wideiv.i = trunc i64 %indvars.iv.i to i32
+  %arrayidx4.phi.trans.insert.i = getelementptr inbounds [0 x i32*]* undef, i64 0, i64 %indvars.iv.i
+  %.pre.i = load i32** %arrayidx4.phi.trans.insert.i, align 8
+  %phitmp.i = add i64 %indvars.iv.i, 1
+  br label %for.body3.i
+}
+
+attributes #0 = { noreturn uwtable "no-frame-pointer-elim"="true" }