[PATCH] D75400: [LICM] Allow freeze to hoist out of a loop

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune updated this revision to Diff 247441.
aqjune added a comment.

Update


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75400/new/

https://reviews.llvm.org/D75400

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


Index: llvm/test/Transforms/LICM/freeze.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LICM/freeze.ll
@@ -0,0 +1,43 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -licm -S < %s | FileCheck %s
+
+define void @hoist(i1 %a) {
+; CHECK-LABEL: @hoist(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = freeze i1 [[A:%.*]]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    call void @use(i1 [[B]])
+; CHECK-NEXT:    br label [[LOOP]]
+;
+entry:
+  br label %loop
+loop:
+  %b = freeze i1 %a
+  call void @use(i1 %b)
+  br label %loop
+}
+
+define i1 @sink(i1 %a) {
+; CHECK-LABEL: @sink(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[C:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[C]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[FR_LE:%.*]] = freeze i1 [[A:%.*]]
+; CHECK-NEXT:    ret i1 [[FR_LE]]
+;
+entry:
+  br label %loop
+loop:
+  %fr = freeze i1 %a
+  %c = call i1 @cond()
+  br i1 %c, label %loop, label %exit
+exit:
+  ret i1 %fr
+}
+
+declare i1 @cond()
+declare void @use(i1)
Index: llvm/lib/Transforms/Scalar/LICM.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LICM.cpp
+++ llvm/lib/Transforms/Scalar/LICM.cpp
@@ -993,7 +993,7 @@
           isa<SelectInst>(I) || isa<GetElementPtrInst>(I) || isa<CmpInst>(I) ||
           isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
           isa<ShuffleVectorInst>(I) || isa<ExtractValueInst>(I) ||
-          isa<InsertValueInst>(I));
+          isa<InsertValueInst>(I) || isa<FreezeInst>(I));
 }
 /// Return true if all of the alias sets within this AST are known not to
 /// contain a Mod, or if MSSA knows thare are no MemoryDefs in the loop.


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