[llvm] f3f8828 - [Attributor] Use known alignment as lower bound to avoid work

[Johannes Doerfert via llvm-commits]

Author: Johannes Doerfert
Date: 2021-03-04T00:35:52-06:00
New Revision: f3f88287c5842dc166d0889cc4474e10b558db0b

URL: https://github.com/llvm/llvm-project/commit/f3f88287c5842dc166d0889cc4474e10b558db0b
DIFF: https://github.com/llvm/llvm-project/commit/f3f88287c5842dc166d0889cc4474e10b558db0b.diff

LOG: [Attributor] Use known alignment as lower bound to avoid work

If we know already more than available from a use, we don't need to
invest time on it.

Added: 
    

Modified: 
    llvm/include/llvm/Transforms/IPO/Attributor.h
    llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    llvm/test/Transforms/Attributor/depgraph.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Transforms/IPO/Attributor.h b/llvm/include/llvm/Transforms/IPO/Attributor.h
index 5ebd0a4b56a9..c8d95f36a514 100644
--- a/llvm/include/llvm/Transforms/IPO/Attributor.h
+++ b/llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -3033,7 +3033,7 @@ struct AADereferenceable
 };
 
 using AAAlignmentStateType =
-    IncIntegerState<uint32_t, Value::MaximumAlignment, 0>;
+    IncIntegerState<uint32_t, Value::MaximumAlignment, 1>;
 /// An abstract interface for all align attributes.
 struct AAAlign : public IRAttribute<
                      Attribute::Alignment,

diff  --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index 4018cf13fc85..54b5b5887d35 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -3679,8 +3679,7 @@ struct AADereferenceableCallSiteReturned final
 
 // ------------------------ Align Argument Attribute ------------------------
 
-static unsigned getKnownAlignForUse(Attributor &A,
-                                    AbstractAttribute &QueryingAA,
+static unsigned getKnownAlignForUse(Attributor &A, AAAlign &QueryingAA,
                                     Value &AssociatedValue, const Use *U,
                                     const Instruction *I, bool &TrackUse) {
   // We need to follow common pointer manipulation uses to the accesses they
@@ -3721,7 +3720,7 @@ static unsigned getKnownAlignForUse(Attributor &A,
       MA = LI->getAlign();
   }
 
-  if (!MA || *MA <= 1)
+  if (!MA || *MA <= QueryingAA.getKnownAlign())
     return 0;
 
   unsigned Alignment = MA->value();

diff  --git a/llvm/test/Transforms/Attributor/depgraph.ll b/llvm/test/Transforms/Attributor/depgraph.ll
index 229144028b18..06b22791a7b1 100644
--- a/llvm/test/Transforms/Attributor/depgraph.ll
+++ b/llvm/test/Transforms/Attributor/depgraph.ll
@@ -130,7 +130,7 @@ define i32* @checkAndAdvance(i32* align 16 %0) {
 ; GRAPH-EMPTY:
 ; GRAPH-NEXT: [AAValueSimplify] for CtxI '  %2 = load i32, i32* %0, align 4' at position {fn_ret:checkAndAdvance [checkAndAdvance at -1]} with state simplified
 ; GRAPH-EMPTY:
-; GRAPH-NEXT: [AAAlign] for CtxI '  %2 = load i32, i32* %0, align 4' at position {fn_ret:checkAndAdvance [checkAndAdvance at -1]} with state align<0-16>
+; GRAPH-NEXT: [AAAlign] for CtxI '  %2 = load i32, i32* %0, align 4' at position {fn_ret:checkAndAdvance [checkAndAdvance at -1]} with state align<1-16>
 ; GRAPH-NEXT:   updates [AAAlign] for CtxI '  %6 = call i32* @checkAndAdvance(i32* %5)' at position {cs_ret: [@-1]} with state align<1-16>
 ; GRAPH-NEXT:   updates [AAAlign] for CtxI '  %6 = call i32* @checkAndAdvance(i32* %5)' at position {cs_ret: [@-1]} with state align<1-16>
 ; GRAPH-EMPTY:
@@ -250,7 +250,7 @@ define i32* @checkAndAdvance(i32* align 16 %0) {
 ; GRAPH-NEXT: [AAIsDead] for CtxI '  br label %8' at position {flt: [@-1]} with state assumed-live
 ; GRAPH-EMPTY:
 ; GRAPH-NEXT: [AAAlign] for CtxI '  %6 = call i32* @checkAndAdvance(i32* %5)' at position {cs_ret: [@-1]} with state align<1-16>
-; GRAPH-NEXT:   updates [AAAlign] for CtxI '  %2 = load i32, i32* %0, align 4' at position {fn_ret:checkAndAdvance [checkAndAdvance at -1]} with state align<0-16>
+; GRAPH-NEXT:   updates [AAAlign] for CtxI '  %2 = load i32, i32* %0, align 4' at position {fn_ret:checkAndAdvance [checkAndAdvance at -1]} with state align<1-16>
 ; GRAPH-EMPTY:
 ; GRAPH-NEXT: [AADereferenceable] for CtxI '  %6 = call i32* @checkAndAdvance(i32* %5)' at position {cs_ret: [@-1]} with state unknown-dereferenceable
 ; GRAPH-EMPTY: