commit 1448d06156728712f47e5a71fac8e8edc0aba73b
author Hal Finkel <hfinkel@anl.gov> Mon Mar 18 17:40:27 2013 +0000
committer Hal Finkel <hfinkel@anl.gov> Mon Mar 18 17:40:27 2013 +0000
tree 8684c3f9dca12a812e8d4d506a6c6f72c25bc099
parent a12c674ee579685e982db008f546681a10cc49a6

Cleanup initial-value constants in PPCCTRLoops

Because the initial-value constants had not been added to the list
of instructions considered for DCE the resulting code had redundant
constant-materialization instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177294 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCCTRLoops.cpp

diff --git a/lib/Target/PowerPC/PPCCTRLoops.cpp b/lib/Target/PowerPC/PPCCTRLoops.cpp
index b98cc48..5165801 100644
--- a/lib/Target/PowerPC/PPCCTRLoops.cpp
+++ b/lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -380,13 +380,13 @@
         assert(InitialValue->isReg() && "Expecting register for init value");
         unsigned InitialValueReg = InitialValue->getReg();
   
-        const MachineInstr *DefInstr = MRI->getVRegDef(InitialValueReg);
+        MachineInstr *DefInstr = MRI->getVRegDef(InitialValueReg);
   
         // Here we need to look for an immediate load (an li or lis/ori pair).
         if (DefInstr && (DefInstr->getOpcode() == PPC::ORI8 ||
                          DefInstr->getOpcode() == PPC::ORI)) {
           int64_t start = (short) DefInstr->getOperand(2).getImm();
-          const MachineInstr *DefInstr2 =
+          MachineInstr *DefInstr2 =
             MRI->getVRegDef(DefInstr->getOperand(0).getReg());
           if (DefInstr2 && (DefInstr2->getOpcode() == PPC::LIS8 ||
                             DefInstr2->getOpcode() == PPC::LIS)) {
@@ -399,6 +399,10 @@
             if ((count % iv_value) != 0) {
               return 0;
             }
+
+            OldInsts.push_back(DefInstr);
+            OldInsts.push_back(DefInstr2);
+
             return new CountValue(count/iv_value);
           }
         } else if (DefInstr && (DefInstr->getOpcode() == PPC::LI8 ||
@@ -409,6 +413,9 @@
           if ((count % iv_value) != 0) {
             return 0;
           }
+
+          OldInsts.push_back(DefInstr);
+
           return new CountValue(count/iv_value);
         } else if (iv_value == 1 || iv_value == -1) {
           // We can't determine a constant starting value.

test/CodeGen/PowerPC/ctr-cleanup.ll

diff --git a/test/CodeGen/PowerPC/ctr-cleanup.ll b/test/CodeGen/PowerPC/ctr-cleanup.ll
new file mode 100644
index 0000000..04e4ffb
--- /dev/null
+++ b/test/CodeGen/PowerPC/ctr-cleanup.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s -mcpu=a2 | FileCheck %s
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+define void @main() #0 {
+entry:
+  br i1 undef, label %for.end, label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 1, %entry ]
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, 5
+  br i1 %exitcond, label %for.end, label %for.body
+
+; CHECK: @main
+; CHECK: li {{[0-9]+}}, 4
+; CHECK-NOT: li {{[0-9]+}}, 4
+; CHECK: bdnz
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }