[llvm] r328058 - [MustExecute] Shwo the effect of using full loop info variant

[Philip Reames via llvm-commits]

Author: reames
Date: Tue Mar 20 16:00:54 2018
New Revision: 328058

URL: http://llvm.org/viewvc/llvm-project?rev=328058&view=rev
Log:
[MustExecute] Shwo the effect of using full loop info variant

Most basic possible test for the logic used by LICM.

Also contains a speculative build fix for compiles which complain about a definition of a stuct K; followed by a declaration as class K;


Modified:
    llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
    llvm/trunk/lib/Analysis/MustExecute.cpp
    llvm/trunk/test/Analysis/MustExecute/loop-header.ll

Modified: llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h?rev=328058&r1=328057&r2=328058&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/LoopUtils.h Tue Mar 20 16:00:54 2018
@@ -40,7 +40,6 @@ class BasicBlock;
 class DataLayout;
 class Loop;
 class LoopInfo;
-class LoopSafetyInfo;
 class OptimizationRemarkEmitter;
 class PredicatedScalarEvolution;
 class PredIteratorCache;

Modified: llvm/trunk/lib/Analysis/MustExecute.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MustExecute.cpp?rev=328058&r1=328057&r2=328058&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MustExecute.cpp (original)
+++ llvm/trunk/lib/Analysis/MustExecute.cpp Tue Mar 20 16:00:54 2018
@@ -185,11 +185,13 @@ FunctionPass *llvm::createMustExecutePri
 }
 
 bool isMustExecuteIn(const Instruction &I, Loop *L, DominatorTree *DT) {
-  // TODO: move loop specific code to analysis
-  //LoopSafetyInfo LSI;
-  //computeLoopSafetyInfo(&LSI, L);
-  //return isGuaranteedToExecute(I, DT, L, &LSI);
-  return isGuaranteedToExecuteForEveryIteration(&I, L);
+  // TODO: merge these two routines.  For the moment, we display the best
+  // result obtained by *either* implementation.  This is a bit unfair since no
+  // caller actually gets the full power at the moment.
+  LoopSafetyInfo LSI;
+  computeLoopSafetyInfo(&LSI, L);
+  return isGuaranteedToExecute(I, DT, L, &LSI) ||
+    isGuaranteedToExecuteForEveryIteration(&I, L);
 }
 
 /// \brief An assembly annotator class to print must execute information in

Modified: llvm/trunk/test/Analysis/MustExecute/loop-header.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/MustExecute/loop-header.ll?rev=328058&r1=328057&r2=328058&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/MustExecute/loop-header.ll (original)
+++ llvm/trunk/test/Analysis/MustExecute/loop-header.ll Tue Mar 20 16:00:54 2018
@@ -88,9 +88,14 @@ exit:
 ; FIXME: handled by loop safety info, test it
 define i1 @nothrow_loop(i32* noalias %p, i32 %high) {
 ; CHECK-LABEL: @nothrow_loop(
-; CHECK-LABEL:       loop:
+; CHECK-LABEL:  loop:
 ; CHECK:         %iv = phi i32 [ 0, %entry ], [ %iv.next, %next ] ; (mustexec in: loop)
 ; CHECK:          br label %next ; (mustexec in: loop)
+; CHECK-LABEL: next:
+; CHECK:          %v = load i32, i32* %p ; (mustexec in: loop)
+; CHECK:          %iv.next = add nuw nsw i32 %iv, 1 ; (mustexec in: loop)
+; CHECK:          %exit.test = icmp slt i32 %iv, %high ; (mustexec in: loop)
+; CHECK:          br i1 %exit.test, label %exit, label %loop ; (mustexec in: loop)
 ; CHECK-NOT: mustexec
 
 entry: