[PATCH] D30263: [LSR] Change default of lsr-exp-narrow to false.

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
Herald added a subscriber: mzolotukhin.

Commit 295704 introduced some benchmark regressions, hopefully characterised by the Shootout-C++/matrix regressions in [1]. The review claimed that this would be committed with the default for the option set to false, but if fact had it enabled. This reverses that default for the time being, in line with the review.

[1] http://llvm.org/perf/db_default/v4/nts/daily_report/2017/2/21?day_start=16


https://reviews.llvm.org/D30263

Files:
  lib/Transforms/Scalar/LoopStrengthReduce.cpp
  test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
  test/Transforms/LoopStrengthReduce/ARM/ivchain-ARM.ll


Index: test/Transforms/LoopStrengthReduce/ARM/ivchain-ARM.ll
===================================================================
--- test/Transforms/LoopStrengthReduce/ARM/ivchain-ARM.ll
+++ test/Transforms/LoopStrengthReduce/ARM/ivchain-ARM.ll
@@ -139,7 +139,7 @@
 ; Consequently, we should *not* form any chains.
 ;
 ; A9: foldedidx:
-; A9: ldrb{{(.w)?}} {{r[0-9]|lr}}, [{{r[0-9]|lr}}, #403]
+; A9: ldrb{{(.w)?}} {{r[0-9]|lr}}, [{{r[0-9]|lr}}, #3]
 define void @foldedidx(i8* nocapture %a, i8* nocapture %b, i8* nocapture %c) nounwind ssp {
 entry:
   br label %for.body
Index: test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
===================================================================
--- test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
+++ test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
@@ -14,7 +14,7 @@
 ; current LSR cost model.
 ; CHECK-NOT: = ptrtoint i8* undef to i64
 ; CHECK: .lr.ph
-; CHECK: [[TMP:%[^ ]+]] = add i64 %4, 1
+; CHECK: [[TMP:%[^ ]+]] = add i64 %tmp5, 1
 ; CHECK: sub i64 [[TMP]], %tmp6
 ; CHECK: ret void
 define void @VerifyDiagnosticConsumerTest() unnamed_addr nounwind uwtable align 2 {
Index: lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -136,7 +136,7 @@
 
 // Flag to choose how to narrow complex lsr solution
 static cl::opt<bool> LSRExpNarrow(
-  "lsr-exp-narrow", cl::Hidden, cl::init(true),
+  "lsr-exp-narrow", cl::Hidden, cl::init(false),
   cl::desc("Narrow LSR complex solution using"
            " expectation of registers number"));
 


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