Flip the new block-placement pass to be on by default.

This is mostly to test the waters. I'd like to get results from FNT
build bots and other bots running on non-x86 platforms.

This feature has been pretty heavily tested over the last few months by
me, and it fixes several of the execution time regressions caused by the
inlining work by preventing inlining decisions from radically impacting
block layout.

I've seen very large improvements in yacr2 and ackermann benchmarks,
along with the expected noise across all of the benchmark suite whenever
code layout changes. I've analyzed all of the regressions and fixed
them, or found them to be impossible to fix. See my email to llvmdev for
more details.

I'd like for this to be in 3.1 as it complements the inliner changes,
but if any failures are showing up or anyone has concerns, it is just
a flag flip and so can be easily turned off.

I'm switching it on tonight to try and get at least one run through
various folks' performance suites in case SPEC or something else has
serious issues with it. I'll watch bots and revert if anything shows up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154816 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 16 insertions, 8 deletions

diff --git a/test/CodeGen/Thumb2/thumb2-branch.ll b/test/CodeGen/Thumb2/thumb2-branch.ll
index 27d8e8fb40..f1c097c189 100644
--- a/test/CodeGen/Thumb2/thumb2-branch.ll
+++ b/test/CodeGen/Thumb2/thumb2-branch.ll
@@ -58,8 +58,8 @@ define i32 @f4(i32 %a, i32 %b, i32* %v) {
 entry:
 ; CHECK: f4:
 ; CHECK: blo LBB
-        %tmp = icmp ult i32 %a, %b              ; <i1> [#uses=1]
-        br i1 %tmp, label %return, label %cond_true
+        %tmp = icmp uge i32 %a, %b              ; <i1> [#uses=1]
+        br i1 %tmp, label %cond_true, label %return
 
 cond_true:              ; preds = %entry
         fence seq_cst
diff --git a/test/CodeGen/Thumb2/thumb2-ifcvt2.ll b/test/CodeGen/Thumb2/thumb2-ifcvt2.ll
index f577f79d69..9a83e65576 100644
--- a/test/CodeGen/Thumb2/thumb2-ifcvt2.ll
+++ b/test/CodeGen/Thumb2/thumb2-ifcvt2.ll
@@ -29,13 +29,13 @@ declare i32 @bar(...)
 define fastcc i32 @CountTree(%struct.quad_struct* %tree) {
 entry:
 ; CHECK: CountTree:
-; CHECK: it eq
-; CHECK: cmpeq
-; CHECK: bne
-; CHECK: cmp
 ; CHECK: itt eq
 ; CHECK: moveq
 ; CHECK: popeq
+; CHECK: bne
+; CHECK: cmp
+; CHECK: it eq
+; CHECK: cmpeq
 	br label %tailrecurse
 
 tailrecurse:		; preds = %bb, %entry
@@ -83,7 +83,7 @@ define fastcc void @t2() nounwind {
 entry:
 ; CHECK: t2:
 ; CHECK: cmp r0, #0
-; CHECK: beq
+; CHECK: bne
 	br i1 undef, label %bb.i.i3, label %growMapping.exit
 
 bb.i.i3:		; preds = %entry
diff --git a/test/CodeGen/Thumb2/thumb2-jtb.ll b/test/CodeGen/Thumb2/thumb2-jtb.ll
index f5a56e5ace..7e1655f6c2 100644
--- a/test/CodeGen/Thumb2/thumb2-jtb.ll
+++ b/test/CodeGen/Thumb2/thumb2-jtb.ll
@@ -3,11 +3,19 @@
 ; Do not use tbb / tbh if any destination is before the jumptable.
 ; rdar://7102917
 
-define i16 @main__getopt_internal_2E_exit_2E_ce(i32) nounwind {
+define i16 @main__getopt_internal_2E_exit_2E_ce(i32, i1 %b) nounwind {
+entry:
+  br i1 %b, label %codeRepl127.exitStub, label %newFuncRoot
+
 newFuncRoot:
 	br label %_getopt_internal.exit.ce
 
 codeRepl127.exitStub:		; preds = %_getopt_internal.exit.ce
+  ; Add an explicit edge back to before the jump table to ensure this block
+  ; is placed first.
+  br i1 %b, label %newFuncRoot, label %codeRepl127.exitStub.exit
+
+codeRepl127.exitStub.exit:
 	ret i16 0
 
 parse_options.exit.loopexit.exitStub:		; preds = %_getopt_internal.exit.ce