[test][LoopUnroll] Cleanup FullUnroll.ll

[aeubanks]

Summary

This is in preparation for enabling proper handling of optnone under the
NPM. Most optimizations won't run on an optnone function.

Previously the test would rely on lots of optimizations to optimize the
IR into a simple infinite loop. This is an optnone function, so clearly
that shouldn't be the case.

This IR was found by printing the module before the LoopFullUnrollerPass ran.

[aeubanks]

friendly ping :)

[asbirlea]

Thank you for making this test more resilient.

llvm/test/Transforms/LoopUnroll/FullUnroll.ll

-; RUN: opt -passes='default<O1>' -disable-verify --mtriple x86_64-pc-linux-gnu -disable-loop-unrolling=true \
-; RUN: -S -o - %s | FileCheck %s
+; RUN: opt -passes='loop-unroll-full' -disable-verify --mtriple x86_64-pc-linux-gnu -S -o - %s | FileCheck %s
 
 ; This checks that the loop full unroller will fire in the new pass manager
 ; when forced via #pragma in the source (or annotation in the code).
-target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
 
-; We don't end up deleting the loop, merely turning it infinite, but we remove
-; everything inside of it so check for the loop structure and absence of
-; conditional branches.
-; CHECK-LABEL: bb
-; CHECK: br label
-; CHECK-NOT: br i1
-; CHECK: br label
+; Completely unroll the inner loop
+; CHECK-LABEL: @foo
+; CHECK: br i1
 ; CHECK-NOT: br i1
 
 ; Function Attrs: noinline nounwind optnone uwtable
-define void @foo() #0 {
+define void @foo() local_unnamed_addr #0 {
 bb:
   %tmp = alloca [5 x i32*], align 16
-  %tmp1 = alloca i32, align 4
-  %tmp2 = alloca i32, align 4
-  store i32 5, i32* %tmp1, align 4
-  br label %bb3
-
-bb3:                                              ; preds = %bb23, %bb
-  %tmp4 = load i32, i32* %tmp1, align 4
-  %tmp5 = icmp ne i32 %tmp4, 0
-  br i1 %tmp5, label %bb6, label %bb24
-
-bb6:                                              ; preds = %bb3
-  store i32 0, i32* %tmp2, align 4
-  br label %bb7
-
-bb7:                                              ; preds = %bb20, %bb6
-  %tmp8 = load i32, i32* %tmp2, align 4
-  %tmp9 = icmp slt i32 %tmp8, 5
-  br i1 %tmp9, label %bb10, label %bb23
-
-bb10:                                             ; preds = %bb7
-  %tmp11 = load i32, i32* %tmp2, align 4
-  %tmp12 = sext i32 %tmp11 to i64
-  %tmp13 = getelementptr inbounds [5 x i32*], [5 x i32*]* %tmp, i64 0, i64 %tmp12
-  %tmp14 = load i32*, i32** %tmp13, align 8
-  %tmp15 = icmp ne i32* %tmp14, null
-  br i1 %tmp15, label %bb16, label %bb19
+  br label %bb7.preheader
 
-bb16:                                             ; preds = %bb10
-  %tmp17 = load i32, i32* %tmp1, align 4
-  %tmp18 = add nsw i32 %tmp17, -1
-  store i32 %tmp18, i32* %tmp1, align 4
-  br label %bb19
-
-bb19:                                             ; preds = %bb16, %bb10
-  br label %bb20
-
-bb20:                                             ; preds = %bb19
-  %tmp21 = load i32, i32* %tmp2, align 4
-  %tmp22 = add nsw i32 %tmp21, 1
-  store i32 %tmp22, i32* %tmp2, align 4
-  br label %bb7, !llvm.loop !1
-
-bb23:                                             ; preds = %bb7
-  br label %bb3
+bb3.loopexit:                                     ; preds = %bb10
+  %spec.select.lcssa = phi i32 [ %spec.select, %bb10 ]
+  %tmp5.not = icmp eq i32 %spec.select.lcssa, 0
+  br i1 %tmp5.not, label %bb24, label %bb7.preheader
+
+bb7.preheader:                                    ; preds = %bb3.loopexit, %bb
+  %tmp1.06 = phi i32 [ 5, %bb ], [ %spec.select.lcssa, %bb3.loopexit ]
+  br label %bb10
+
+bb10:                                             ; preds = %bb10, %bb7.preheader
+  %indvars.iv = phi i64 [ 0, %bb7.preheader ], [ %indvars.iv.next, %bb10 ]
+  %tmp1.14 = phi i32 [ %tmp1.06, %bb7.preheader ], [ %spec.select, %bb10 ]
+  %tmp13 = getelementptr inbounds [5 x i32*], [5 x i32*]* %tmp, i64 0, i64 %indvars.iv
+  %tmp14 = load i32*, i32** %tmp13, align 8
+  %tmp15.not = icmp ne i32* %tmp14, null
+  %tmp18 = sext i1 %tmp15.not to i32
+  %spec.select = add nsw i32 %tmp1.14, %tmp18
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond.not = icmp eq i64 %indvars.iv.next, 5
+  br i1 %exitcond.not, label %bb3.loopexit, label %bb10, !llvm.loop !1
 
-bb24:                                             ; preds = %bb3
+bb24:                                             ; preds = %bb3.loopexit
   ret void
 }
 
 attributes #0 = { noinline nounwind optnone uwtable }
 
 !llvm.module.flags = !{!0}
 
 !0 = !{i32 1, !"wchar_size", i32 4}
 !1 = distinct !{!1, !2}
 !2 = !{!"llvm.loop.unroll.full"}