Cleanup trip-count finding for PPC CTR loops (and some bug fixes).

This cleans up the method used to find trip counts in order to form CTR loops on PPC.
This refactoring allows the pass to find loops which have a constant trip count but also
happen to end with a comparison to zero. This also adds explicit FIXMEs to mark two different
classes of loops that are currently ignored.

In addition, we now search through all potential induction operations instead of just the first.
Also, we check the predicate code on the conditional branch and abort the transformation if the
code is not EQ or NE, and we then make sure that the branch to be transformed matches the
condition register defined by the comparison (multiple possible comparisons will be considered).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158607 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 134 insertions, 0 deletions

diff --git a/test/CodeGen/PowerPC/ctrloop-sums.ll b/test/CodeGen/PowerPC/ctrloop-sums.ll
new file mode 100644
index 0000000000..eae8c38eee
--- /dev/null
+++ b/test/CodeGen/PowerPC/ctrloop-sums.ll
@@ -0,0 +1,134 @@
+; ModuleID = 'SingleSource/Regression/C/sumarray2d.c'
+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-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+; RUN: llc < %s -march=ppc64 | FileCheck %s
+
+@.str = private unnamed_addr constant [23 x i8] c"Sum(Array[%d,%d] = %d\0A\00", align 1
+
+define i32 @SumArray([100 x i32]* nocapture %Array, i32 %NumI, i32 %NumJ) nounwind readonly {
+entry:
+  %cmp12 = icmp eq i32 %NumI, 0
+  br i1 %cmp12, label %for.end8, label %for.cond1.preheader.lr.ph
+
+for.cond1.preheader.lr.ph:                        ; preds = %entry
+  %cmp29 = icmp eq i32 %NumJ, 0
+  br i1 %cmp29, label %for.inc6, label %for.body3.lr.ph.us
+
+for.inc6.us:                                      ; preds = %for.body3.us
+  %indvars.iv.next17 = add i64 %indvars.iv16, 1
+  %lftr.wideiv18 = trunc i64 %indvars.iv.next17 to i32
+  %exitcond19 = icmp eq i32 %lftr.wideiv18, %NumI
+  br i1 %exitcond19, label %for.end8, label %for.body3.lr.ph.us
+
+for.body3.us:                                     ; preds = %for.body3.us, %for.body3.lr.ph.us
+  %indvars.iv = phi i64 [ 0, %for.body3.lr.ph.us ], [ %indvars.iv.next, %for.body3.us ]
+  %Result.111.us = phi i32 [ %Result.014.us, %for.body3.lr.ph.us ], [ %add.us, %for.body3.us ]
+  %arrayidx5.us = getelementptr inbounds [100 x i32]* %Array, i64 %indvars.iv16, i64 %indvars.iv
+  %0 = load i32* %arrayidx5.us, align 4, !tbaa !0
+  %add.us = add nsw i32 %0, %Result.111.us
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %NumJ
+  br i1 %exitcond, label %for.inc6.us, label %for.body3.us
+
+for.body3.lr.ph.us:                               ; preds = %for.inc6.us, %for.cond1.preheader.lr.ph
+  %indvars.iv16 = phi i64 [ %indvars.iv.next17, %for.inc6.us ], [ 0, %for.cond1.preheader.lr.ph ]
+  %Result.014.us = phi i32 [ %add.us, %for.inc6.us ], [ 0, %for.cond1.preheader.lr.ph ]
+  br label %for.body3.us
+
+for.inc6:                                         ; preds = %for.inc6, %for.cond1.preheader.lr.ph
+  %i.013 = phi i32 [ %inc7, %for.inc6 ], [ 0, %for.cond1.preheader.lr.ph ]
+  %inc7 = add i32 %i.013, 1
+  %exitcond20 = icmp eq i32 %inc7, %NumI
+  br i1 %exitcond20, label %for.end8, label %for.inc6
+
+for.end8:                                         ; preds = %for.inc6.us, %for.inc6, %entry
+  %Result.0.lcssa = phi i32 [ 0, %entry ], [ %add.us, %for.inc6.us ], [ 0, %for.inc6 ]
+  ret i32 %Result.0.lcssa
+; CHECK: @SumArray
+; CHECK: mtctr
+; CHECK: bdnz
+}
+
+define i32 @main() nounwind {
+entry:
+  %Array = alloca [100 x [100 x i32]], align 4
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv33 = phi i64 [ 0, %entry ], [ %indvars.iv.next34, %for.body ]
+  %0 = trunc i64 %indvars.iv33 to i32
+  %sub = sub i32 0, %0
+  %arrayidx2 = getelementptr inbounds [100 x [100 x i32]]* %Array, i64 0, i64 %indvars.iv33, i64 %indvars.iv33
+  store i32 %sub, i32* %arrayidx2, align 4, !tbaa !0
+  %indvars.iv.next34 = add i64 %indvars.iv33, 1
+  %lftr.wideiv35 = trunc i64 %indvars.iv.next34 to i32
+  %exitcond36 = icmp eq i32 %lftr.wideiv35, 100
+  br i1 %exitcond36, label %for.cond6.preheader, label %for.body
+
+for.cond6.preheader:                              ; preds = %for.body, %for.inc17
+  %indvars.iv29 = phi i64 [ %indvars.iv.next30, %for.inc17 ], [ 0, %for.body ]
+  br label %for.body8
+
+for.body8:                                        ; preds = %for.inc14, %for.cond6.preheader
+  %indvars.iv = phi i64 [ 0, %for.cond6.preheader ], [ %indvars.iv.next, %for.inc14 ]
+  %1 = trunc i64 %indvars.iv to i32
+  %2 = trunc i64 %indvars.iv29 to i32
+  %cmp9 = icmp eq i32 %1, %2
+  br i1 %cmp9, label %for.inc14, label %if.then
+
+if.then:                                          ; preds = %for.body8
+  %3 = add i64 %indvars.iv, %indvars.iv29
+  %arrayidx13 = getelementptr inbounds [100 x [100 x i32]]* %Array, i64 0, i64 %indvars.iv29, i64 %indvars.iv
+  %4 = trunc i64 %3 to i32
+  store i32 %4, i32* %arrayidx13, align 4, !tbaa !0
+  br label %for.inc14
+
+for.inc14:                                        ; preds = %for.body8, %if.then
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv27 = trunc i64 %indvars.iv.next to i32
+  %exitcond28 = icmp eq i32 %lftr.wideiv27, 100
+  br i1 %exitcond28, label %for.inc17, label %for.body8
+
+for.inc17:                                        ; preds = %for.inc14
+  %indvars.iv.next30 = add i64 %indvars.iv29, 1
+  %lftr.wideiv31 = trunc i64 %indvars.iv.next30 to i32
+  %exitcond32 = icmp eq i32 %lftr.wideiv31, 100
+  br i1 %exitcond32, label %for.body3.lr.ph.us.i, label %for.cond6.preheader
+
+for.inc6.us.i:                                    ; preds = %for.body3.us.i
+  %indvars.iv.next17.i = add i64 %indvars.iv16.i, 1
+  %lftr.wideiv24 = trunc i64 %indvars.iv.next17.i to i32
+  %exitcond25 = icmp eq i32 %lftr.wideiv24, 100
+  br i1 %exitcond25, label %SumArray.exit, label %for.body3.lr.ph.us.i
+
+for.body3.us.i:                                   ; preds = %for.body3.lr.ph.us.i, %for.body3.us.i
+  %indvars.iv.i = phi i64 [ 0, %for.body3.lr.ph.us.i ], [ %indvars.iv.next.i, %for.body3.us.i ]
+  %Result.111.us.i = phi i32 [ %Result.014.us.i, %for.body3.lr.ph.us.i ], [ %add.us.i, %for.body3.us.i ]
+  %arrayidx5.us.i = getelementptr inbounds [100 x [100 x i32]]* %Array, i64 0, i64 %indvars.iv16.i, i64 %indvars.iv.i
+  %5 = load i32* %arrayidx5.us.i, align 4, !tbaa !0
+  %add.us.i = add nsw i32 %5, %Result.111.us.i
+  %indvars.iv.next.i = add i64 %indvars.iv.i, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next.i to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, 100
+  br i1 %exitcond, label %for.inc6.us.i, label %for.body3.us.i
+
+for.body3.lr.ph.us.i:                             ; preds = %for.inc17, %for.inc6.us.i
+  %indvars.iv16.i = phi i64 [ %indvars.iv.next17.i, %for.inc6.us.i ], [ 0, %for.inc17 ]
+  %Result.014.us.i = phi i32 [ %add.us.i, %for.inc6.us.i ], [ 0, %for.inc17 ]
+  br label %for.body3.us.i
+
+SumArray.exit:                                    ; preds = %for.inc6.us.i
+  %call20 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([23 x i8]* @.str, i64 0, i64 0), i32 100, i32 100, i32 %add.us.i) nounwind
+  ret i32 0
+
+; CHECK: @main
+; CHECK: mtctr
+; CHECK: bdnz
+}
+
+declare i32 @printf(i8* nocapture, ...) nounwind
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}