[PATCH] D17356: Fix PR26655: Bail out if all the registers of an instruction in a BUNDLE already have the correct kill flag.

[Mandeep Singh Grang via llvm-commits]

mgrang updated the summary for this revision.
mgrang removed rL LLVM as the repository for this revision.
mgrang updated this revision to Diff 50764.
Herald added a subscriber: MatzeB.

http://reviews.llvm.org/D17356

Files:
  lib/CodeGen/ScheduleDAGInstrs.cpp
  test/CodeGen/Thumb2/thumb2-cpsr-liveness.ll

Index: test/CodeGen/Thumb2/thumb2-cpsr-liveness.ll
===================================================================
--- /dev/null
+++ test/CodeGen/Thumb2/thumb2-cpsr-liveness.ll
@@ -0,0 +1,41 @@
+; RUN: llc < %s -mtriple=thumbv7-linux-gnueabi -misched-postra=true
+
+define i32 @test_cpsr() {
+entry:
+  %a = alloca [10 x i32], align 4
+  %0 = bitcast [10 x i32]* %a to i8*
+  %arrayidx.gep = getelementptr [10 x i32], [10 x i32]* %a, i32 0, i32 0
+  br label %for.body
+
+for.cond.cleanup:
+  %c.1.reg2mem.0.lcssa = phi i32 [ %c.1.reg2mem.0, %for.inc ]
+  ret i32 %c.1.reg2mem.0.lcssa
+
+for.body:
+  %1 = phi i32 [ 0, %entry ], [ %.pre, %for.inc.for.body_crit_edge ]
+  %c.018.reg2mem.0 = phi i32 [ 0, %entry ], [ %c.1.reg2mem.0, %for.inc.for.body_crit_edge ]
+  %b.017.reg2mem.0 = phi double [ 0.000000e+00, %entry ], [ %b.1.reg2mem.0, %for.inc.for.body_crit_edge ]
+  %arrayidx.phi = phi i32* [ %arrayidx.gep, %entry ], [ %arrayidx.inc, %for.inc.for.body_crit_edge ]
+  %i.019 = phi i32 [ 0, %entry ], [ %inc, %for.inc.for.body_crit_edge ]
+  %cmp1 = icmp slt i32 %1, 10
+  %arrayidx.inc = getelementptr i32, i32* %arrayidx.phi, i32 1
+  br i1 %cmp1, label %for.inc, label %if.end
+
+if.end:
+  %conv = sitofp i32 %i.019 to double
+  %cmp2 = fcmp nsz ogt double %conv, %b.017.reg2mem.0
+  %selv = select i1 %cmp2, double %conv, double %b.017.reg2mem.0
+  %selv7 = select i1 %cmp2, i32 %i.019, i32 %c.018.reg2mem.0
+  br label %for.inc
+
+for.inc:
+  %b.1.reg2mem.0 = phi double [ %b.017.reg2mem.0, %for.body ], [ %selv, %if.end ]
+  %c.1.reg2mem.0 = phi i32 [ %c.018.reg2mem.0, %for.body ], [ %selv7, %if.end ]
+  %exitcond = icmp eq i32 %i.019, 9
+  br i1 %exitcond, label %for.cond.cleanup, label %for.inc.for.body_crit_edge
+
+for.inc.for.body_crit_edge:
+  %inc = add nuw nsw i32 %i.019, 1
+  %.pre = load i32, i32* %arrayidx.inc, align 4
+  br label %for.body
+}
Index: lib/CodeGen/ScheduleDAGInstrs.cpp
===================================================================
--- lib/CodeGen/ScheduleDAGInstrs.cpp
+++ lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -1203,6 +1203,7 @@
   MachineBasicBlock::instr_iterator Begin = MI->getIterator();
   MachineBasicBlock::instr_iterator End = getBundleEnd(*MI);
   while (Begin != End) {
+    bool KillStateAlreadySet = true;
     for (MachineOperand &MO : (--End)->operands()) {
       if (!MO.isReg() || MO.isDef() || Reg != MO.getReg())
         continue;
@@ -1219,12 +1220,19 @@
       if (MO.isInternalRead())
         continue;
 
+      // The current operand already has the correct kill flag set.
       if (MO.isKill() == NewKillState)
         continue;
       MO.setIsKill(NewKillState);
+      KillStateAlreadySet = false;
+
       if (NewKillState)
         return;
     }
+	// If the kill flag is already set on all the operands of the instruction
+	// then bail out.
+	if (NewKillState && KillStateAlreadySet)
+      return;
   }
 }
 


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