[CVP] Infer range return attribute #99620

nikic · 2024-07-19T09:32:34Z

We already infer this in IPSCCP (which runs very early, so cannot benefit from inlining and simplifications) and SCCP (which runs without PredicateInfo, so does not use assumes). Do it in CVP as well, so it can handle cases that IPSCCP/SCCP can't.

Fixes #98946 (everything apart from f2, where the assume is dropped by the frontend).

(No compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=f1ff3a279f3320d8e0d4abbc1a8357bb51de25a2&to=46ab5f809414b3f06ab9956e0fc6910284417b6d&stat=instructions:u)

We already infer this in IPSCCP, but as that pass runs very early, it cannot make use of simplifications (in particular post-inline simplifications). This fixes most cases from llvm#98946 (everything apart from f2 where the assume is dropped).

llvmbot · 2024-09-19T13:22:31Z

@llvm/pr-subscribers-hlsl
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-llvm-transforms

Author: Nikita Popov (nikic)

Changes

We already infer this in IPSCCP (which runs very early, so cannot benefit from inlining and simplifications) and SCCP (which runs without PredicateInfo, so does not use assumes). Do it in CVP as well, so it can handle cases that IPSCCP/SCCP can't.

Fixes #98946 (everything apart from f2, where the assume is dropped by the frontend).

(No compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=f1ff3a279f3320d8e0d4abbc1a8357bb51de25a2&to=46ab5f809414b3f06ab9956e0fc6910284417b6d&stat=instructions:u)

Full diff: https://github.com/llvm/llvm-project/pull/99620.diff

7 Files Affected:

(modified) llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp (+18)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/add.ll (+1-1)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/ashr.ll (+4-4)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/basic.ll (+9-9)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/cond-using-block-value.ll (+1-1)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/select.ll (+2-2)
(modified) llvm/test/Transforms/CorrelatedValuePropagation/vectors.ll (+16-16)

diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index 95de8eceb6be59..ed2bddd0521967 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -1207,6 +1207,11 @@ static bool processAnd(BinaryOperator *BinOp, LazyValueInfo *LVI) {
 static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
                     const SimplifyQuery &SQ) {
   bool FnChanged = false;
+  std::optional<ConstantRange> RetRange;
+  if (F.hasExactDefinition() && F.getReturnType()->isIntOrIntVectorTy())
+    RetRange =
+        ConstantRange::getEmpty(F.getReturnType()->getScalarSizeInBits());
+
   // Visiting in a pre-order depth-first traversal causes us to simplify early
   // blocks before querying later blocks (which require us to analyze early
   // blocks).  Eagerly simplifying shallow blocks means there is strictly less
@@ -1277,6 +1282,11 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
       // constant folding the return values of callees.
       auto *RetVal = RI->getReturnValue();
       if (!RetVal) break; // handle "ret void"
+      if (RetRange && !RetRange->isFullSet())
+        RetRange =
+            RetRange->unionWith(LVI->getConstantRange(RetVal, RI,
+                                                      /*UndefAllowed=*/false));
+
       if (isa<Constant>(RetVal)) break; // nothing to do
       if (auto *C = getConstantAt(RetVal, RI, LVI)) {
         ++NumReturns;
@@ -1289,6 +1299,14 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
     FnChanged |= BBChanged;
   }
 
+  // Infer range attribute on return value.
+  if (RetRange && !RetRange->isFullSet()) {
+    Attribute RangeAttr = F.getRetAttribute(Attribute::Range);
+    if (RangeAttr.isValid())
+      RetRange = RetRange->intersectWith(RangeAttr.getRange());
+    if (!RetRange->isEmptySet() && !RetRange->isSingleElement())
+      F.addRangeRetAttr(*RetRange);
+  }
   return FnChanged;
 }
 
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/add.ll b/llvm/test/Transforms/CorrelatedValuePropagation/add.ll
index b29a496ab1deb9..b1151cdf26ffd5 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/add.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/add.ll
@@ -311,7 +311,7 @@ exit:
 
 @limit = external global i32
 define i32 @test11(ptr %p, i32 %i) {
-; CHECK-LABEL: define i32 @test11(
+; CHECK-LABEL: define range(i32 0, 2147483645) i32 @test11(
 ; CHECK-SAME: ptr [[P:%.*]], i32 [[I:%.*]]) {
 ; CHECK-NEXT:    [[LIMIT:%.*]] = load i32, ptr [[P]], align 4, !range [[RNG0:![0-9]+]]
 ; CHECK-NEXT:    [[WITHIN_1:%.*]] = icmp ugt i32 [[LIMIT]], [[I]]
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/ashr.ll b/llvm/test/Transforms/CorrelatedValuePropagation/ashr.ll
index 25bec18a5dbf37..f719effac113e9 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/ashr.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/ashr.ll
@@ -159,7 +159,7 @@ exit:
 
 ; check that ashr of -1 or 0 is optimized away
 define i32 @test6(i32 %f, i32 %g) {
-; CHECK-LABEL: define i32 @test6(
+; CHECK-LABEL: define range(i32 -1, 1) i32 @test6(
 ; CHECK-SAME: i32 [[F:%.*]], i32 [[G:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[F]], 1
@@ -177,7 +177,7 @@ entry:
 
 ; same test as above with different numbers
 define i32 @test7(i32 %f, i32 %g) {
-; CHECK-LABEL: define i32 @test7(
+; CHECK-LABEL: define range(i32 -1, 1) i32 @test7(
 ; CHECK-SAME: i32 [[F:%.*]], i32 [[G:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = and i32 [[F]], -2
@@ -197,7 +197,7 @@ entry:
 
 ; check that ashr of -2 or 1 is not optimized away
 define i32 @test8(i32 %f, i32 %g, i1 %s) {
-; CHECK-LABEL: define i32 @test8(
+; CHECK-LABEL: define range(i32 -2, 2) i32 @test8(
 ; CHECK-SAME: i32 [[F:%.*]], i32 [[G:%.*]], i1 [[S:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = ashr i32 -2, [[F]]
@@ -213,7 +213,7 @@ entry:
 }
 
 define i32 @may_including_undef(i1 %c.1, i1 %c.2) {
-; CHECK-LABEL: define i32 @may_including_undef(
+; CHECK-LABEL: define range(i32 -1073741824, 1073741824) i32 @may_including_undef(
 ; CHECK-SAME: i1 [[C_1:%.*]], i1 [[C_2:%.*]]) {
 ; CHECK-NEXT:    br i1 [[C_1]], label %[[TRUE_1:.*]], label %[[FALSE:.*]]
 ; CHECK:       [[TRUE_1]]:
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll b/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
index c529bab4ef4a72..3c3b1d4bef45bb 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
@@ -3,7 +3,7 @@
 ; PR2581
 
 define i32 @test1(i1 %C) {
-; CHECK-LABEL: define i32 @test1
+; CHECK-LABEL: define range(i32 10, 12) i32 @test1
 ; CHECK-SAME: (i1 [[C:%.*]]) {
 ; CHECK-NEXT:    br i1 [[C]], label [[EXIT:%.*]], label [[BODY:%.*]]
 ; CHECK:       body:
@@ -82,7 +82,7 @@ bb2:
 
 ; PR1757
 define i32 @test4(i32) {
-; CHECK-LABEL: define i32 @test4
+; CHECK-LABEL: define range(i32 0, 3) i32 @test4
 ; CHECK-SAME: (i32 [[TMP0:%.*]]) {
 ; CHECK-NEXT:  EntryBlock:
 ; CHECK-NEXT:    [[DOTDEMORGAN:%.*]] = icmp sgt i32 [[TMP0]], 2
@@ -210,7 +210,7 @@ return:
 }
 
 define i32 @switch1(i32 %s) {
-; CHECK-LABEL: define i32 @switch1
+; CHECK-LABEL: define range(i32 -1, 2) i32 @switch1
 ; CHECK-SAME: (i32 [[S:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[S]], 0
@@ -250,7 +250,7 @@ next:
 }
 
 define i32 @switch2(i32 %s) {
-; CHECK-LABEL: define i32 @switch2
+; CHECK-LABEL: define range(i32 -1, 2) i32 @switch2
 ; CHECK-SAME: (i32 [[S:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[S]], 0
@@ -284,7 +284,7 @@ next:
 }
 
 define i32 @switch3(i32 %s) {
-; CHECK-LABEL: define i32 @switch3
+; CHECK-LABEL: define range(i32 -1, 2) i32 @switch3
 ; CHECK-SAME: (i32 [[S:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[S]], 0
@@ -451,7 +451,7 @@ unreachable:
 }
 
 define i32 @switch_range(i32 %cond) {
-; CHECK-LABEL: define i32 @switch_range
+; CHECK-LABEL: define range(i32 1, 3) i32 @switch_range
 ; CHECK-SAME: (i32 [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[S:%.*]] = urem i32 [[COND]], 3
@@ -491,7 +491,7 @@ unreachable:
 ; switch condition, we should not change the default.
 
 define i32 @switch_range_not_full(i32 %cond) {
-; CHECK-LABEL: define i32 @switch_range_not_full
+; CHECK-LABEL: define range(i32 0, 3) i32 @switch_range_not_full
 ; CHECK-SAME: (i32 [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[S:%.*]] = urem i32 [[COND]], 3
@@ -2052,7 +2052,7 @@ define i1 @binop_eval_order(i32 %x) {
 }
 
 define range(i32 0, 1024) i32 @range_larger(i8 %x) {
-; CHECK-LABEL: define range(i32 0, 1024) i32 @range_larger
+; CHECK-LABEL: define range(i32 0, 256) i32 @range_larger
 ; CHECK-SAME: (i8 [[X:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[X]] to i32
 ; CHECK-NEXT:    ret i32 [[ZEXT]]
@@ -2072,7 +2072,7 @@ define range(i32 0, 128) i32 @range_smaller(i8 %x) {
 }
 
 define range(i32 128, 512) i32 @range_intersect(i8 %x) {
-; CHECK-LABEL: define range(i32 128, 512) i32 @range_intersect
+; CHECK-LABEL: define range(i32 128, 256) i32 @range_intersect
 ; CHECK-SAME: (i8 [[X:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[X]] to i32
 ; CHECK-NEXT:    ret i32 [[ZEXT]]
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/cond-using-block-value.ll b/llvm/test/Transforms/CorrelatedValuePropagation/cond-using-block-value.ll
index 252f6596cedc5e..a7a1803bccc263 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/cond-using-block-value.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/cond-using-block-value.ll
@@ -38,7 +38,7 @@ end:
 }
 
 define i64 @test_sext_from_implied_cond(i32 %a, i32 %b) {
-; CHECK-LABEL: define i64 @test_sext_from_implied_cond(
+; CHECK-LABEL: define range(i64 0, 2147483647) i64 @test_sext_from_implied_cond(
 ; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
 ; CHECK-NEXT:    [[A_CMP:%.*]] = icmp slt i32 [[A]], 0
 ; CHECK-NEXT:    br i1 [[A_CMP]], label [[END:%.*]], label [[L1:%.*]]
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/select.ll b/llvm/test/Transforms/CorrelatedValuePropagation/select.ll
index 2054b0fc99d499..be027fbc698744 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/select.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/select.ll
@@ -141,7 +141,7 @@ else:
 }
 
 define i8 @not_correlated(i1, i1) {
-; CHECK-LABEL: define i8 @not_correlated
+; CHECK-LABEL: define range(i8 0, 2) i8 @not_correlated
 ; CHECK-SAME: (i1 [[TMP0:%.*]], i1 [[TMP1:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[S:%.*]] = select i1 [[TMP0]], i8 0, i8 1
@@ -361,7 +361,7 @@ exit:
 }
 
 define i64 @select_cond_may_undef(i32 %a) {
-; CHECK-LABEL: define i64 @select_cond_may_undef
+; CHECK-LABEL: define range(i64 -2147483648, 2147483648) i64 @select_cond_may_undef
 ; CHECK-SAME: (i32 [[A:%.*]]) {
 ; CHECK-NEXT:    [[IS_A_NONNEGATIVE:%.*]] = icmp sgt i32 [[A]], 1
 ; CHECK-NEXT:    [[NARROW:%.*]] = select i1 [[IS_A_NONNEGATIVE]], i32 [[A]], i32 0
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/vectors.ll b/llvm/test/Transforms/CorrelatedValuePropagation/vectors.ll
index 351a2c79cdff42..bda270e99bc2e6 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/vectors.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/vectors.ll
@@ -60,7 +60,7 @@ define <2 x i1> @cmp_signedness(<2 x i8> %a) {
 }
 
 define <2 x i16> @infer_nowrap(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @infer_nowrap(
+; CHECK-LABEL: define range(i16 1, 257) <2 x i16> @infer_nowrap(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nuw nsw <2 x i16> [[ZEXT]], <i16 1, i16 1>
@@ -72,7 +72,7 @@ define <2 x i16> @infer_nowrap(<2 x i8> %a) {
 }
 
 define <2 x i16> @infer_nowrap_nonsplat(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @infer_nowrap_nonsplat(
+; CHECK-LABEL: define range(i16 1, 258) <2 x i16> @infer_nowrap_nonsplat(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nuw nsw <2 x i16> [[ZEXT]], <i16 1, i16 2>
@@ -84,7 +84,7 @@ define <2 x i16> @infer_nowrap_nonsplat(<2 x i8> %a) {
 }
 
 define <vscale x 2 x i16> @infer_nowrap_scalable(<vscale x 2 x i8> %a) {
-; CHECK-LABEL: define <vscale x 2 x i16> @infer_nowrap_scalable(
+; CHECK-LABEL: define range(i16 1, 257) <vscale x 2 x i16> @infer_nowrap_scalable(
 ; CHECK-SAME: <vscale x 2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <vscale x 2 x i8> [[A]] to <vscale x 2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nuw nsw <vscale x 2 x i16> [[ZEXT]], shufflevector (<vscale x 2 x i16> insertelement (<vscale x 2 x i16> poison, i16 1, i64 0), <vscale x 2 x i16> poison, <vscale x 2 x i32> zeroinitializer)
@@ -96,7 +96,7 @@ define <vscale x 2 x i16> @infer_nowrap_scalable(<vscale x 2 x i8> %a) {
 }
 
 define <2 x i16> @infer_nowrap_poison(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @infer_nowrap_poison(
+; CHECK-LABEL: define range(i16 1, 257) <2 x i16> @infer_nowrap_poison(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nuw nsw <2 x i16> [[ZEXT]], <i16 1, i16 poison>
@@ -108,7 +108,7 @@ define <2 x i16> @infer_nowrap_poison(<2 x i8> %a) {
 }
 
 define <2 x i16> @infer_nowrap_nonsplat_nsw_only(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @infer_nowrap_nonsplat_nsw_only(
+; CHECK-LABEL: define range(i16 -1, 257) <2 x i16> @infer_nowrap_nonsplat_nsw_only(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nsw <2 x i16> [[ZEXT]], <i16 1, i16 -1>
@@ -120,7 +120,7 @@ define <2 x i16> @infer_nowrap_nonsplat_nsw_only(<2 x i8> %a) {
 }
 
 define <2 x i16> @abs(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @abs(
+; CHECK-LABEL: define range(i16 0, 256) <2 x i16> @abs(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    ret <2 x i16> [[ZEXT]]
@@ -131,7 +131,7 @@ define <2 x i16> @abs(<2 x i8> %a) {
 }
 
 define <2 x i16> @saturating(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @saturating(
+; CHECK-LABEL: define range(i16 1, 257) <2 x i16> @saturating(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = add nuw nsw <2 x i16> [[ZEXT]], <i16 1, i16 1>
@@ -156,7 +156,7 @@ define {<2 x i16>, <2 x i1>} @with_overflow(<2 x i8> %a) {
 }
 
 define <2 x i16> @srem1(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @srem1(
+; CHECK-LABEL: define range(i16 0, 42) <2 x i16> @srem1(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES1_LHS_TRUNC:%.*]] = trunc <2 x i16> [[ZEXT]] to <2 x i8>
@@ -170,7 +170,7 @@ define <2 x i16> @srem1(<2 x i8> %a) {
 }
 
 define <2 x i16> @srem2(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @srem2(
+; CHECK-LABEL: define range(i16 -41, 42) <2 x i16> @srem2(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = sext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES_LHS_TRUNC:%.*]] = trunc <2 x i16> [[ZEXT]] to <2 x i8>
@@ -184,7 +184,7 @@ define <2 x i16> @srem2(<2 x i8> %a) {
 }
 
 define <2 x i16> @ashr(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @ashr(
+; CHECK-LABEL: define range(i16 0, 128) <2 x i16> @ashr(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = lshr <2 x i16> [[ZEXT]], <i16 1, i16 1>
@@ -196,7 +196,7 @@ define <2 x i16> @ashr(<2 x i8> %a) {
 }
 
 define <2 x i32> @sext(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i32> @sext(
+; CHECK-LABEL: define range(i32 0, 256) <2 x i32> @sext(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    [[RES:%.*]] = zext nneg <2 x i16> [[ZEXT]] to <2 x i32>
@@ -220,7 +220,7 @@ define <2 x float> @sitofp(<2 x i8> %a) {
 }
 
 define <2 x i16> @and(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @and(
+; CHECK-LABEL: define range(i16 0, 256) <2 x i16> @and(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    ret <2 x i16> [[ZEXT]]
@@ -231,7 +231,7 @@ define <2 x i16> @and(<2 x i8> %a) {
 }
 
 define <2 x i16> @and_with_poison(<2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @and_with_poison(
+; CHECK-LABEL: define range(i16 0, 256) <2 x i16> @and_with_poison(
 ; CHECK-SAME: <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
 ; CHECK-NEXT:    ret <2 x i16> [[ZEXT]]
@@ -242,7 +242,7 @@ define <2 x i16> @and_with_poison(<2 x i8> %a) {
 }
 
 define <4 x i64> @issue_97674_getConstantOnEdge(i1 %cond) {
-; CHECK-LABEL: define <4 x i64> @issue_97674_getConstantOnEdge(
+; CHECK-LABEL: define range(i64 0, 2) <4 x i64> @issue_97674_getConstantOnEdge(
 ; CHECK-SAME: i1 [[COND:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_END:.*]]
@@ -277,7 +277,7 @@ entry:
 }
 
 define <2 x i16> @phi_merge1(i1 %c, <2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @phi_merge1(
+; CHECK-LABEL: define range(i16 2, 259) <2 x i16> @phi_merge1(
 ; CHECK-SAME: i1 [[C:%.*]], <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>
@@ -303,7 +303,7 @@ join:
 }
 
 define <2 x i16> @phi_merge2(i1 %c, <2 x i8> %a) {
-; CHECK-LABEL: define <2 x i16> @phi_merge2(
+; CHECK-LABEL: define range(i16 2, 259) <2 x i16> @phi_merge2(
 ; CHECK-SAME: i1 [[C:%.*]], <2 x i8> [[A:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[A]] to <2 x i16>

nikic · 2024-09-19T13:23:55Z

llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp

+    Attribute RangeAttr = F.getRetAttribute(Attribute::Range);
+    if (RangeAttr.isValid())
+      RetRange = RetRange->intersectWith(RangeAttr.getRange());
+    if (!RetRange->isEmptySet() && !RetRange->isSingleElement())


I've excluded the single element case to make this less spammy. I didn't want to have range attributes on every single function returning a constant (in which case IPSCCP would already propagate the cosntant).

Maybe leave that as a comment?

dtcxzyw · 2024-09-19T15:26:41Z

Missing fold: https://alive2.llvm.org/ce/z/2rmc3h
See dtcxzyw/llvm-opt-benchmark#1342 (comment)

goldsteinn · 2024-09-19T17:03:28Z

llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp

+    if (RangeAttr.isValid())
+      RetRange = RetRange->intersectWith(RangeAttr.getRange());
+    if (!RetRange->isEmptySet() && !RetRange->isSingleElement())
+      F.addRangeRetAttr(*RetRange);


Missing FnChanged = true?

Good point, fixed.

Could we cause an inf loop if existing range attr is same as new one?

nikic · 2024-09-20T10:41:11Z

Missing fold: https://alive2.llvm.org/ce/z/2rmc3h See dtcxzyw/llvm-opt-benchmark#1342 (comment)

In principle, I think this could be supported by making decomposeBitTestICmp detect that ugt 255 means & 256 == 1 together with information from computeConstantRange(). Not sure if it's worth it...

dtcxzyw

LGTM. Thank you!

nikic force-pushed the cvp-ret-range branch 2 times, most recently from 23bdf84 to b9128bc Compare July 19, 2024 10:39

nikic mentioned this pull request Aug 30, 2024

[SCCP] Infer return attributes in SCCP as well #106732

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[CVP] Infer range return attribute

46ab5f8

We already infer this in IPSCCP, but as that pass runs very early, it cannot make use of simplifications (in particular post-inline simplifications). This fixes most cases from llvm#98946 (everything apart from f2 where the assume is dropped).

nikic force-pushed the cvp-ret-range branch from b9128bc to 46ab5f8 Compare September 19, 2024 13:05

nikic marked this pull request as ready for review September 19, 2024 13:21

llvmbot added the llvm:transforms label Sep 19, 2024

nikic requested review from fhahn, dtcxzyw and goldsteinn September 19, 2024 13:22

nikic commented Sep 19, 2024

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This was referenced Sep 19, 2024

Task submission dtcxzyw/llvm-opt-benchmark#1312

Open

Fuzz PR99620 dtcxzyw/llvm-fuzz-service#22

Closed

pre-commit: PR99620 dtcxzyw/llvm-opt-benchmark#1342

Closed

Fix clang test

599bf84

llvmbot added clang Clang issues not falling into any other category HLSL HLSL Language Support labels Sep 19, 2024

goldsteinn reviewed Sep 19, 2024

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review feedback

f8c7ecf

dtcxzyw mentioned this pull request Sep 20, 2024

pre-commit: PR99620 dtcxzyw/llvm-opt-benchmark#1353

Closed

dtcxzyw approved these changes Sep 20, 2024

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nikic merged commit 3127b65 into llvm:main Sep 20, 2024
6 of 8 checks passed

nikic deleted the cvp-ret-range branch September 20, 2024 12:29

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