[llvm] 05b060b - [LoopPeel] Expose ValueMap of last peeled iteration. NFC

[Anna Thomas via llvm-commits]

Author: Anna Thomas
Date: 2022-12-19T09:55:29-05:00
New Revision: 05b060b0b07bf35131a94d62575dc091bd03b2f0

URL: https://github.com/llvm/llvm-project/commit/05b060b0b07bf35131a94d62575dc091bd03b2f0
DIFF: https://github.com/llvm/llvm-project/commit/05b060b0b07bf35131a94d62575dc091bd03b2f0.diff

LOG: [LoopPeel] Expose ValueMap of last peeled iteration. NFC

The value map of last peeled iteration is computed within peelLoop API.
This patch exposes it for callers of peelLoop.
While this is not currently used by upstream passes, we have a usecase
downstream which benefits from this API update. Future users of peelLoop
can also use the ValueMap if needed.

Similar value maps are exposed by other loop utilities such as loop
cloning.

Differential Revision: https://reviews.llvm.org/D138228

Added: 
    

Modified: 
    llvm/include/llvm/Transforms/Utils/LoopPeel.h
    llvm/lib/Transforms/Scalar/LoopFuse.cpp
    llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
    llvm/lib/Transforms/Utils/LoopPeel.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Transforms/Utils/LoopPeel.h b/llvm/include/llvm/Transforms/Utils/LoopPeel.h
index 7dffaa4d3d9c..0b78700ca71b 100644
--- a/llvm/include/llvm/Transforms/Utils/LoopPeel.h
+++ b/llvm/include/llvm/Transforms/Utils/LoopPeel.h
@@ -15,13 +15,17 @@
 #define LLVM_TRANSFORMS_UTILS_LOOPPEEL_H
 
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
 
 namespace llvm {
 
 bool canPeel(const Loop *L);
 
+/// VMap is the value-map that maps instructions from the original loop to
+/// instructions in the last peeled-off iteration.
 bool peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI, ScalarEvolution *SE,
-              DominatorTree &DT, AssumptionCache *AC, bool PreserveLCSSA);
+              DominatorTree &DT, AssumptionCache *AC, bool PreserveLCSSA,
+              ValueToValueMapTy &VMap);
 
 TargetTransformInfo::PeelingPreferences
 gatherPeelingPreferences(Loop *L, ScalarEvolution &SE,

diff  --git a/llvm/lib/Transforms/Scalar/LoopFuse.cpp b/llvm/lib/Transforms/Scalar/LoopFuse.cpp
index 3e879a2ce6bd..77323f18774e 100644
--- a/llvm/lib/Transforms/Scalar/LoopFuse.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopFuse.cpp
@@ -767,7 +767,8 @@ struct LoopFuser {
     LLVM_DEBUG(dbgs() << "Attempting to peel first " << PeelCount
                       << " iterations of the first loop. \n");
 
-    FC0.Peeled = peelLoop(FC0.L, PeelCount, &LI, &SE, DT, &AC, true);
+    ValueToValueMapTy VMap;
+    FC0.Peeled = peelLoop(FC0.L, PeelCount, &LI, &SE, DT, &AC, true, VMap);
     if (FC0.Peeled) {
       LLVM_DEBUG(dbgs() << "Done Peeling\n");
 

diff  --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 34ac98fee475..1a6065cb3f1a 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -1292,7 +1292,8 @@ tryToUnrollLoop(Loop *L, DominatorTree &DT, LoopInfo *LI, ScalarEvolution &SE,
              << " iterations";
     });
 
-    if (peelLoop(L, PP.PeelCount, LI, &SE, DT, &AC, PreserveLCSSA)) {
+    ValueToValueMapTy VMap;
+    if (peelLoop(L, PP.PeelCount, LI, &SE, DT, &AC, PreserveLCSSA, VMap)) {
       simplifyLoopAfterUnroll(L, true, LI, &SE, &DT, &AC, &TTI);
       // If the loop was peeled, we already "used up" the profile information
       // we had, so we don't want to unroll or peel again.

diff  --git a/llvm/lib/Transforms/Utils/LoopPeel.cpp b/llvm/lib/Transforms/Utils/LoopPeel.cpp
index 6721948009e1..2acbe9002309 100644
--- a/llvm/lib/Transforms/Utils/LoopPeel.cpp
+++ b/llvm/lib/Transforms/Utils/LoopPeel.cpp
@@ -854,7 +854,7 @@ llvm::gatherPeelingPreferences(Loop *L, ScalarEvolution &SE,
 /// optimizations.
 bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
                     ScalarEvolution *SE, DominatorTree &DT, AssumptionCache *AC,
-                    bool PreserveLCSSA) {
+                    bool PreserveLCSSA, ValueToValueMapTy &LVMap) {
   assert(PeelCount > 0 && "Attempt to peel out zero iterations?");
   assert(canPeel(L) && "Attempt to peel a loop which is not peelable?");
 
@@ -946,8 +946,6 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
   InsertBot->setName(Header->getName() + ".peel.next");
   NewPreHeader->setName(PreHeader->getName() + ".peel.newph");
 
-  ValueToValueMapTy LVMap;
-
   Instruction *LatchTerm =
       cast<Instruction>(cast<BasicBlock>(Latch)->getTerminator());