moved sink between sink and hoist

Author: VigneshwarJ

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -479,6 +479,12 @@ bool LoopInvariantCodeMotion::runOnLoop(Loop *L, AAResults *AA, LoopInfo *LI,
                                     TLI, TTI, L, MSSAU, &SafetyInfo, Flags, ORE)
             : sinkRegion(DT->getNode(L->getHeader()), AA, LI, DT, TLI, TTI, L,
                          MSSAU, &SafetyInfo, Flags, ORE);
+
+  // sink pre-header defs that are unused in-loop into the unique exit to reduce
+  // pressure.
+  Changed |= sinkUnusedInvariantsFromPreheaderToExit(L, AA, &SafetyInfo, MSSAU,
+                                                     SE, DT, Flags, ORE);
+
   Flags.setIsSink(false);
   if (Preheader)
     Changed |= hoistRegion(DT->getNode(L->getHeader()), AA, LI, DT, AC, TLI, L,
@@ -551,18 +557,11 @@ bool LoopInvariantCodeMotion::runOnLoop(Loop *L, AAResults *AA, LoopInfo *LI,
   assert((L->isOutermost() || L->getParentLoop()->isLCSSAForm(*DT)) &&
          "Parent loop not left in LCSSA form after LICM!");
 
-  // sink pre-header defs that are unused in-loop into the unique exit to reduce
-  // pressure.
-  Flags.setIsSink(true);
-  Changed |= sinkUnusedInvariantsFromPreheaderToExit(L, AA, &SafetyInfo, MSSAU,
-                                                     SE, DT, Flags, ORE);
-
   if (VerifyMemorySSA)
     MSSA->verifyMemorySSA();
 
   if (Changed && SE)
     SE->forgetLoopDispositions();
-
   return Changed;
 }
 

llvm/test/Transforms/LICM/scalar-promote.ll

@@ -44,6 +44,7 @@ define void @test2(i32 %i) {
 ; CHECK-SAME: i32 [[I:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    [[X2:%.*]] = getelementptr i32, ptr @X, i64 1
+; CHECK-NEXT:    [[X3:%.*]] = getelementptr i32, ptr @X, i64 1
 ; CHECK-NEXT:    [[X1_PROMOTED:%.*]] = load i32, ptr [[X2]], align 4
 ; CHECK-NEXT:    br label %[[LOOP:.*]]
 ; CHECK:       [[LOOP]]:
@@ -52,7 +53,6 @@ define void @test2(i32 %i) {
 ; CHECK-NEXT:    br i1 false, label %[[LOOP]], label %[[EXIT:.*]]
 ; CHECK:       [[EXIT]]:
 ; CHECK-NEXT:    [[V_LCSSA:%.*]] = phi i32 [ [[V]], %[[LOOP]] ]
-; CHECK-NEXT:    [[X3:%.*]] = getelementptr i32, ptr @X, i64 1
 ; CHECK-NEXT:    store i32 [[V_LCSSA]], ptr [[X2]], align 4
 ; CHECK-NEXT:    ret void
 ;

llvm/test/Transforms/LICM/sink-from-preheader.ll

@@ -63,6 +63,7 @@ exit:
 define i32 @test_with_unused_load_modified_store(i32 %a, ptr %b, i32 %N) {
 ; CHECK-LABEL: @test_with_unused_load_modified_store(
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LOAD:%.*]] = load i32, ptr [[B:%.*]], align 4
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
 ; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
@@ -71,9 +72,8 @@ define i32 @test_with_unused_load_modified_store(i32 %a, ptr %b, i32 %N) {
 ; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[SMAX:%.*]] = phi i32 [ [[IV_NEXT]], [[LOOP]] ]
-; CHECK-NEXT:    [[LOAD:%.*]] = load i32, ptr [[B:%.*]], align 4
-; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A]], [[LOAD]]
 ; CHECK-NEXT:    store i32 [[SMAX]], ptr [[B]], align 4
+; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A]], [[LOAD]]
 ; CHECK-NEXT:    ret i32 [[ADD]]
 ;
 entry: