[PATCH] D149374: [LICM] Hoist widenable condition when it's the only non-invariant operand of its user

[Aleksandr Popov via Phabricator via llvm-commits]

aleksandr.popov updated this revision to Diff 517736.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149374/new/

https://reviews.llvm.org/D149374

Files:
  llvm/lib/Transforms/Scalar/LICM.cpp
  llvm/test/Transforms/LICM/explicit_guards.ll


Index: llvm/test/Transforms/LICM/explicit_guards.ll
===================================================================
--- llvm/test/Transforms/LICM/explicit_guards.ll
+++ llvm/test/Transforms/LICM/explicit_guards.ll
@@ -133,14 +133,14 @@
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[LOAD:%.*]] = load atomic i32, ptr [[P:%.*]] unordered, align 8
 ; CHECK-NEXT:    [[ICMP7:%.*]] = icmp ult i32 0, [[LOAD]]
+; CHECK-NEXT:    [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
+; CHECK-NEXT:    [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[ICMP7]], [[WIDENABLE_COND]]
 ; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
 ; CHECK:       loop.header:
 ; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    [[ICMP:%.*]] = icmp ult i32 [[IV]], [[X:%.*]]
 ; CHECK-NEXT:    br i1 [[ICMP]], label [[LOOP_BODY:%.*]], label [[EXIT:%.*]]
 ; CHECK:       loop.body:
-; CHECK-NEXT:    [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
-; CHECK-NEXT:    [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[ICMP7]], [[WIDENABLE_COND]]
 ; CHECK-NEXT:    br i1 [[EXIPLICIT_GUARD_COND]], label [[GUARDED1:%.*]], label [[DEOPT:%.*]], !prof [[PROF0]]
 ; CHECK:       deopt:
 ; CHECK-NEXT:    call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) [ "deopt"() ]
Index: llvm/lib/Transforms/Scalar/LICM.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LICM.cpp
+++ llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1237,6 +1237,19 @@
       // Assumes don't actually alias anything or throw
       return true;
 
+    if (match(CI, m_Intrinsic<Intrinsic::experimental_widenable_condition>())) {
+      // Hoist widenable condition when it's the only non-invariant operand of
+      // its user
+      for (const Use &U : CI->uses())
+        if (const Instruction *UI = dyn_cast<Instruction>(U.getUser()))
+          for (const Use &Op : UI->operands()) {
+            const Instruction *OpI = dyn_cast<Instruction>(Op.get());
+            if (OpI && OpI != &I && !CurLoop->isLoopInvariant(OpI))
+              return false;
+          }
+      return true;
+    }
+
     // Handle simple cases by querying alias analysis.
     MemoryEffects Behavior = AA->getMemoryEffects(CI);
     if (Behavior.doesNotAccessMemory())


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