[flang-commits] [flang] 2e637db - [flang] Canonicalize redundant pointer converts. (#121864)
via flang-commits
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Tue Jan 7 08:35:47 PST 2025
Author: Slava Zakharin
Date: 2025-01-07T08:35:43-08:00
New Revision: 2e637dbbb8bc9a41f8eabd1df347ca2559b1abd7
URL: https://github.com/llvm/llvm-project/commit/2e637dbbb8bc9a41f8eabd1df347ca2559b1abd7
DIFF: https://github.com/llvm/llvm-project/commit/2e637dbbb8bc9a41f8eabd1df347ca2559b1abd7.diff
LOG: [flang] Canonicalize redundant pointer converts. (#121864)
This patch adds a canonicalization pattern for optimizing redundant
"pointer" fir.converts. Such converts prevent the StackArrays pass
to recognize fir.freemem for the corresponding fir.allocmem, e.g.:
```
%69 = fir.allocmem !fir.array<2xi32>
%71:2 = hlfir.declare %69(%70) {uniq_name = ".tmp.arrayctor"} :
(!fir.heap<!fir.array<2xi32>>, !fir.shape<1>) ->
(!fir.heap<!fir.array<2xi32>>, !fir.heap<!fir.array<2xi32>>)
%95 = fir.convert %71#1 :
(!fir.heap<!fir.array<2xi32>>) -> !fir.ref<!fir.array<2xi32>>
%100 = fir.convert %95 :
(!fir.ref<!fir.array<2xi32>>) -> !fir.heap<!fir.array<2xi32>>
fir.freemem %100 : !fir.heap<!fir.array<2xi32>>
```
I found this in `tonto`, but the change does not affect performance at all.
Anyway, it looks like a reasonable thing to do, and it makes easier
to compare the performance profiles with other compilers'.
Added:
Modified:
flang/include/flang/Optimizer/Dialect/CanonicalizationPatterns.td
flang/lib/Optimizer/Dialect/FIROps.cpp
flang/test/Fir/convert-fold.fir
flang/test/Lower/array-substring.f90
flang/test/Lower/vector-subscript-io.f90
Removed:
################################################################################
diff --git a/flang/include/flang/Optimizer/Dialect/CanonicalizationPatterns.td b/flang/include/flang/Optimizer/Dialect/CanonicalizationPatterns.td
index 1dbde5c1c73024..2414de496d45bc 100644
--- a/flang/include/flang/Optimizer/Dialect/CanonicalizationPatterns.td
+++ b/flang/include/flang/Optimizer/Dialect/CanonicalizationPatterns.td
@@ -57,6 +57,9 @@ def StrictSmallerWidthPred : Constraint<CPred<
"$0.getType().getIntOrFloatBitWidth() < "
"$1.getType().getIntOrFloatBitWidth()">>;
+def PointerCompatiblePred
+ : Constraint<CPred<"fir::ConvertOp::isPointerCompatible($0.getType())">>;
+
// floats or ints that undergo successive extensions or successive truncations.
def ConvertConvertOptPattern
: Pat<(fir_ConvertOp:$res (fir_ConvertOp:$irm $arg)),
@@ -112,4 +115,18 @@ def ForwardConstantConvertPattern
(createConstantOp $res, $attr),
[(IndexTypePred $res), (IntegerTypePred $cnt)]>;
+// Optimize redundant pointer conversions, e.g.:
+// %1 = fir.convert %0 :
+// (!fir.heap<!fir.array<2xf32>>) -> !fir.ref<!fir.array<2xf32>>
+// %2 = fir.convert %1 :
+// (!fir.ref<!fir.array<2xf32>>) -> !fir.heap<!fir.array<2xf32>>
+// Will be optimized into:
+// %2 = fir.convert %0 :
+// (!fir.heap<!fir.array<2xf32>>) -> !fir.heap<!fir.array<2xf32>>
+// which is redundant due to RedundantConvertOptPattern.
+def ChainedPointerConvertsPattern
+ : Pat<(fir_ConvertOp:$res(fir_ConvertOp:$irm $arg)), (fir_ConvertOp $arg),
+ [(PointerCompatiblePred $arg), (PointerCompatiblePred $irm),
+ (PointerCompatiblePred $res)]>;
+
#endif // FORTRAN_FIR_REWRITE_PATTERNS
diff --git a/flang/lib/Optimizer/Dialect/FIROps.cpp b/flang/lib/Optimizer/Dialect/FIROps.cpp
index cdcf9bda49a627..fa83aa380e489c 100644
--- a/flang/lib/Optimizer/Dialect/FIROps.cpp
+++ b/flang/lib/Optimizer/Dialect/FIROps.cpp
@@ -1313,7 +1313,8 @@ void fir::ConvertOp::getCanonicalizationPatterns(
results.insert<ConvertConvertOptPattern, ConvertAscendingIndexOptPattern,
ConvertDescendingIndexOptPattern, RedundantConvertOptPattern,
CombineConvertOptPattern, CombineConvertTruncOptPattern,
- ForwardConstantConvertPattern>(context);
+ ForwardConstantConvertPattern, ChainedPointerConvertsPattern>(
+ context);
}
mlir::OpFoldResult fir::ConvertOp::fold(FoldAdaptor adaptor) {
diff --git a/flang/test/Fir/convert-fold.fir b/flang/test/Fir/convert-fold.fir
index ebb6c8db7c891c..fb30e634ba5e6d 100644
--- a/flang/test/Fir/convert-fold.fir
+++ b/flang/test/Fir/convert-fold.fir
@@ -35,3 +35,12 @@ func.func @ctest() -> index {
// CHECK-NEXT: return %{{.*}} : index
return %2 : index
}
+
+// CHECK-LABEL: func.func @ptrtest(
+// CHECK-SAME: %[[VAL_0:.*]]: !fir.heap<!fir.array<2xf32>>) -> !fir.heap<!fir.array<2xf32>> {
+func.func @ptrtest(%0 : !fir.heap<!fir.array<2xf32>>) -> !fir.heap<!fir.array<2xf32>> {
+ %1 = fir.convert %0 : (!fir.heap<!fir.array<2xf32>>) -> !fir.ref<!fir.array<2xf32>>
+ %2 = fir.convert %1 : (!fir.ref<!fir.array<2xf32>>) -> !fir.heap<!fir.array<2xf32>>
+// CHECK: return %[[VAL_0]] : !fir.heap<!fir.array<2xf32>>
+ return %2 : !fir.heap<!fir.array<2xf32>>
+}
diff --git a/flang/test/Lower/array-substring.f90 b/flang/test/Lower/array-substring.f90
index 02101039120e9f..7544fbb989627b 100644
--- a/flang/test/Lower/array-substring.f90
+++ b/flang/test/Lower/array-substring.f90
@@ -24,9 +24,8 @@
! CHECK: %[[VAL_16:.*]] = fir.array_coor %[[VAL_7]](%[[VAL_9]]) {{\[}}%[[VAL_10]]] %[[VAL_15]] : (!fir.ref<!fir.array<1x!fir.char<1,12>>>, !fir.shape<1>, !fir.slice<1>, index) -> !fir.ref<!fir.char<1,12>>
! CHECK: %[[VAL_17:.*]] = fir.convert %[[VAL_16]] : (!fir.ref<!fir.char<1,12>>) -> !fir.ref<!fir.array<12x!fir.char<1>>>
! CHECK: %[[VAL_18:.*]] = fir.coordinate_of %[[VAL_17]], %[[VAL_2]] : (!fir.ref<!fir.array<12x!fir.char<1>>>, index) -> !fir.ref<!fir.char<1>>
-! CHECK: %[[VAL_19:.*]] = fir.convert %[[VAL_18]] : (!fir.ref<!fir.char<1>>) -> !fir.ref<!fir.char<1,?>>
! CHECK: %[[VAL_20:.*]] = fir.array_coor %[[VAL_11]](%[[VAL_9]]) %[[VAL_15]] : (!fir.ref<!fir.array<1x!fir.char<1,8>>>, !fir.shape<1>, index) -> !fir.ref<!fir.char<1,8>>
-! CHECK: %[[VAL_21:.*]] = fir.convert %[[VAL_19]] : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<i8>
+! CHECK: %[[VAL_21:.*]] = fir.convert %[[VAL_18]] : (!fir.ref<!fir.char<1>>) -> !fir.ref<i8>
! CHECK: %[[VAL_22:.*]] = fir.convert %[[VAL_20]] : (!fir.ref<!fir.char<1,8>>) -> !fir.ref<i8>
! CHECK: %[[VAL_23:.*]] = fir.convert %[[VAL_4]] : (index) -> i64
! CHECK: %[[VAL_24:.*]] = fir.call @_FortranACharacterCompareScalar1(%[[VAL_21]], %[[VAL_22]], %[[VAL_23]], %[[VAL_23]]) {{.*}}: (!fir.ref<i8>, !fir.ref<i8>, i64, i64) -> i32
diff --git a/flang/test/Lower/vector-subscript-io.f90 b/flang/test/Lower/vector-subscript-io.f90
index 372130fd099074..9a041af16c88cc 100644
--- a/flang/test/Lower/vector-subscript-io.f90
+++ b/flang/test/Lower/vector-subscript-io.f90
@@ -325,12 +325,11 @@ subroutine substring(x, y, i, j)
! CHECK: %[[VAL_230:.*]] = arith.subi %[[VAL_216]], %[[VAL_210]] : index
! CHECK: %[[VAL_231:.*]] = fir.convert %[[VAL_228]] : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<!fir.array<?x!fir.char<1>>>
! CHECK: %[[VAL_232:.*]] = fir.coordinate_of %[[VAL_231]], %[[VAL_230]] : (!fir.ref<!fir.array<?x!fir.char<1>>>, index) -> !fir.ref<!fir.char<1>>
-! CHECK: %[[VAL_233:.*]] = fir.convert %[[VAL_232]] : (!fir.ref<!fir.char<1>>) -> !fir.ref<!fir.char<1,?>>
! CHECK: %[[VAL_234:.*]] = arith.subi %[[VAL_219]], %[[VAL_216]] : index
! CHECK: %[[VAL_235:.*]] = arith.addi %[[VAL_234]], %[[VAL_210]] : index
! CHECK: %[[VAL_236:.*]] = arith.cmpi slt, %[[VAL_235]], %[[VAL_209]] : index
! CHECK: %[[VAL_237:.*]] = arith.select %[[VAL_236]], %[[VAL_209]], %[[VAL_235]] : index
-! CHECK: %[[VAL_238:.*]] = fir.convert %[[VAL_233]] : (!fir.ref<!fir.char<1,?>>) -> !fir.ref<i8>
+! CHECK: %[[VAL_238:.*]] = fir.convert %[[VAL_232]] : (!fir.ref<!fir.char<1>>) -> !fir.ref<i8>
! CHECK: %[[VAL_239:.*]] = fir.convert %[[VAL_237]] : (index) -> i64
! CHECK: %[[VAL_240:.*]] = fir.call @_FortranAioInputAscii(%[[VAL_213]], %[[VAL_238]], %[[VAL_239]]) {{.*}}: (!fir.ref<i8>, !fir.ref<i8>, i64) -> i1
! CHECK: %[[VAL_241:.*]] = arith.addi %[[VAL_221]], %[[VAL_210]] overflow<nsw> : index
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