[llvm] 203cc66 - [PHITransAddr] Simplify casts in PHITransAddr

[Sergey Kachkov via llvm-commits]

Author: Sergey Kachkov
Date: 2023-02-07T12:43:19+03:00
New Revision: 203cc665cf01015736677bbe794161aad155a8df

URL: https://github.com/llvm/llvm-project/commit/203cc665cf01015736677bbe794161aad155a8df
DIFF: https://github.com/llvm/llvm-project/commit/203cc665cf01015736677bbe794161aad155a8df.diff

LOG: [PHITransAddr] Simplify casts in PHITransAddr

Try to simplify cast in similar way as for GEP and ADD with
constant (e.g. sext/zext + trunc).

Differential Revision: https://reviews.llvm.org/D143167

Added: 
    

Modified: 
    llvm/lib/Analysis/PHITransAddr.cpp
    llvm/test/Transforms/GVN/PRE/phi-translate-2.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/PHITransAddr.cpp b/llvm/lib/Analysis/PHITransAddr.cpp
index 3da92770dc6ca..5700fd664a4cd 100644
--- a/llvm/lib/Analysis/PHITransAddr.cpp
+++ b/llvm/lib/Analysis/PHITransAddr.cpp
@@ -177,10 +177,12 @@ Value *PHITransAddr::translateSubExpr(Value *V, BasicBlock *CurBB,
 
     // Find an available version of this cast.
 
-    // Constants are trivial to find.
-    if (Constant *C = dyn_cast<Constant>(PHIIn))
-      return addAsInput(
-          ConstantExpr::getCast(Cast->getOpcode(), C, Cast->getType()));
+    // Try to simplify cast first.
+    if (Value *V = simplifyCastInst(Cast->getOpcode(), PHIIn, Cast->getType(),
+                                    {DL, TLI, DT, AC})) {
+      RemoveInstInputs(PHIIn, InstInputs);
+      return addAsInput(V);
+    }
 
     // Otherwise we have to see if a casted version of the incoming pointer
     // is available.  If so, we can use it, otherwise we have to fail.

diff  --git a/llvm/test/Transforms/GVN/PRE/phi-translate-2.ll b/llvm/test/Transforms/GVN/PRE/phi-translate-2.ll
index d968716d42873..46fde7a0a48c1 100644
--- a/llvm/test/Transforms/GVN/PRE/phi-translate-2.ll
+++ b/llvm/test/Transforms/GVN/PRE/phi-translate-2.ll
@@ -306,18 +306,21 @@ while.end:
 define i32 @test7(ptr noalias %ptr1, ptr noalias %ptr2, i32 %i, i1 %cond) {
 ; CHECK-LABEL: @test7(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    br i1 [[COND:%.*]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
+; CHECK-NEXT:    br i1 [[COND:%.*]], label [[IF_THEN:%.*]], label [[ENTRY_IF_END_CRIT_EDGE:%.*]]
+; CHECK:       entry.if.end_crit_edge:
+; CHECK-NEXT:    [[RES_PRE:%.*]] = load i32, ptr [[PTR1:%.*]], align 4
+; CHECK-NEXT:    br label [[IF_END:%.*]]
 ; CHECK:       if.then:
-; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[PTR1:%.*]], i32 [[I:%.*]]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[PTR1]], i32 [[I:%.*]]
 ; CHECK-NEXT:    [[TMP:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
 ; CHECK-NEXT:    store i32 [[TMP]], ptr [[PTR2:%.*]], align 4
 ; CHECK-NEXT:    [[IDX_EXT:%.*]] = sext i32 [[I]] to i64
 ; CHECK-NEXT:    br label [[IF_END]]
 ; CHECK:       if.end:
-; CHECK-NEXT:    [[IDX:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IDX_EXT]], [[IF_THEN]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ [[RES_PRE]], [[ENTRY_IF_END_CRIT_EDGE]] ], [ [[TMP]], [[IF_THEN]] ]
+; CHECK-NEXT:    [[IDX:%.*]] = phi i64 [ 0, [[ENTRY_IF_END_CRIT_EDGE]] ], [ [[IDX_EXT]], [[IF_THEN]] ]
 ; CHECK-NEXT:    [[IDX_TRUNC:%.*]] = trunc i64 [[IDX]] to i32
 ; CHECK-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[PTR1]], i32 [[IDX_TRUNC]]
-; CHECK-NEXT:    [[RES:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
 ; CHECK-NEXT:    ret i32 [[RES]]
 ;
 entry: