[llvm] daa9af1 - [FuncSpec] Handle ssa_copy intrinsic calls in InstCostVisitor (#114247)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 4 02:09:54 PST 2024
Author: Hari Limaye
Date: 2024-11-04T10:09:50Z
New Revision: daa9af179f5967e90cd45cec35ead793a4166679
URL: https://github.com/llvm/llvm-project/commit/daa9af179f5967e90cd45cec35ead793a4166679
DIFF: https://github.com/llvm/llvm-project/commit/daa9af179f5967e90cd45cec35ead793a4166679.diff
LOG: [FuncSpec] Handle ssa_copy intrinsic calls in InstCostVisitor (#114247)
Look through ssa_copy intrinsic calls when computing codesize bonus for
a specialization.
Also remove redundant logic to skip computing codesize bonus for
ssa_copy intrinsics, now these are considered zero-cost by TTI (in PR
#75294).
Added:
llvm/test/Transforms/FunctionSpecialization/ssa-copy.ll
Modified:
llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
index 919d3143a13f7e..1efec22624dd4f 100644
--- a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -120,10 +120,6 @@ Cost InstCostVisitor::estimateBasicBlocks(
continue;
for (Instruction &I : *BB) {
- // Disregard SSA copies.
- if (auto *II = dyn_cast<IntrinsicInst>(&I))
- if (II->getIntrinsicID() == Intrinsic::ssa_copy)
- continue;
// If it's a known constant we have already accounted for it.
if (KnownConstants.contains(&I))
continue;
@@ -402,6 +398,14 @@ Constant *InstCostVisitor::visitFreezeInst(FreezeInst &I) {
}
Constant *InstCostVisitor::visitCallBase(CallBase &I) {
+ assert(LastVisited != KnownConstants.end() && "Invalid iterator!");
+
+ // Look through calls to ssa_copy intrinsics.
+ if (auto *II = dyn_cast<IntrinsicInst>(&I);
+ II && II->getIntrinsicID() == Intrinsic::ssa_copy) {
+ return LastVisited->second;
+ }
+
Function *F = I.getCalledFunction();
if (!F || !canConstantFoldCallTo(&I, F))
return nullptr;
diff --git a/llvm/test/Transforms/FunctionSpecialization/ssa-copy.ll b/llvm/test/Transforms/FunctionSpecialization/ssa-copy.ll
new file mode 100644
index 00000000000000..aaafe294480b24
--- /dev/null
+++ b/llvm/test/Transforms/FunctionSpecialization/ssa-copy.ll
@@ -0,0 +1,113 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs --version 5
+; RUN: opt -passes=print-predicateinfo -disable-output -S < %s 2>&1 | FileCheck %s --check-prefix=PREDINF
+; RUN: opt -passes="ipsccp<func-spec>" -funcspec-min-function-size=1 \
+; RUN: -funcspec-for-literal-constant=true \
+; RUN: -funcspec-min-codesize-savings=50 \
+; RUN: -funcspec-min-latency-savings=0 \
+; RUN: -S < %s | FileCheck %s --check-prefix=FUNCSPEC
+
+; Verify that we are able to estimate the codesize savings by looking through
+; calls to ssa_copy intrinsics, which are inserted by PredicateInfo when IPSCCP
+; is run prior to FunctionSpecialization.
+define i32 @main() {
+entry:
+ %res = call i32 @test_ssa_copy(i32 0)
+ ret i32 %res
+}
+
+define i32 @test_ssa_copy(i32 %x) {
+entry:
+ br label %block1
+
+block1:
+ %cmp = icmp eq i32 %x, 0
+ br i1 %cmp, label %block2, label %exit1
+
+block2:
+ br i1 %cmp, label %block3, label %exit2
+
+block3:
+ br i1 %cmp, label %exit4, label %exit3
+
+exit1:
+ ret i32 %x
+
+exit2:
+ ret i32 %x
+
+exit3:
+ ret i32 %x
+
+exit4:
+ ret i32 999
+}
+; PREDINF-LABEL: define i32 @main() {
+; PREDINF-NEXT: [[ENTRY:.*:]]
+; PREDINF-NEXT: [[RES:%.*]] = call i32 @test_ssa_copy(i32 0)
+; PREDINF-NEXT: ret i32 [[RES]]
+;
+;
+; PREDINF-LABEL: define i32 @test_ssa_copy(
+; PREDINF-SAME: i32 [[X:%.*]]) {
+; PREDINF-NEXT: [[ENTRY:.*:]]
+; PREDINF-NEXT: br label %[[BLOCK1:.*]]
+; PREDINF: [[BLOCK1]]:
+; PREDINF-NEXT: [[CMP:%.*]] = icmp eq i32 [[X]], 0
+; PREDINF: [[CMP_0:%.*]] = call i1 @llvm.ssa.copy.i1(i1 [[CMP]])
+; PREDINF: [[X_0:%.*]] = call i32 @llvm.ssa.copy.i32(i32 [[X]])
+; PREDINF: [[X_4:%.*]] = call i32 @llvm.ssa.copy.i32(i32 [[X]])
+; PREDINF-NEXT: br i1 [[CMP]], label %[[BLOCK2:.*]], label %[[EXIT1:.*]]
+; PREDINF: [[BLOCK2]]:
+; PREDINF: [[CMP_0_1:%.*]] = call i1 @llvm.ssa.copy.i1(i1 [[CMP_0]])
+; PREDINF: [[X_0_1:%.*]] = call i32 @llvm.ssa.copy.i32(i32 [[X_0]])
+; PREDINF: [[X_0_3:%.*]] = call i32 @llvm.ssa.copy.i32(i32 [[X_0]])
+; PREDINF-NEXT: br i1 [[CMP_0]], label %[[BLOCK3:.*]], label %[[EXIT2:.*]]
+; PREDINF: [[BLOCK3]]:
+; PREDINF: [[X_0_1_2:%.*]] = call i32 @llvm.ssa.copy.i32(i32 [[X_0_1]])
+; PREDINF-NEXT: br i1 [[CMP_0_1]], label %[[EXIT4:.*]], label %[[EXIT3:.*]]
+; PREDINF: [[EXIT1]]:
+; PREDINF-NEXT: ret i32 [[X_4]]
+; PREDINF: [[EXIT2]]:
+; PREDINF-NEXT: ret i32 [[X_0_3]]
+; PREDINF: [[EXIT3]]:
+; PREDINF-NEXT: ret i32 [[X_0_1_2]]
+; PREDINF: [[EXIT4]]:
+; PREDINF-NEXT: ret i32 999
+;
+;
+; FUNCSPEC-LABEL: define i32 @main() {
+; FUNCSPEC-NEXT: [[ENTRY:.*:]]
+; FUNCSPEC-NEXT: [[RES:%.*]] = call i32 @test_ssa_copy.specialized.1(i32 0)
+; FUNCSPEC-NEXT: ret i32 999
+;
+;
+; FUNCSPEC-LABEL: define range(i32 1, 0) i32 @test_ssa_copy(
+; FUNCSPEC-SAME: i32 [[X:%.*]]) {
+; FUNCSPEC-NEXT: [[ENTRY:.*:]]
+; FUNCSPEC-NEXT: br label %[[BLOCK1:.*]]
+; FUNCSPEC: [[BLOCK1]]:
+; FUNCSPEC-NEXT: [[CMP:%.*]] = icmp eq i32 [[X]], 0
+; FUNCSPEC-NEXT: br i1 [[CMP]], label %[[BLOCK2:.*]], label %[[EXIT1:.*]]
+; FUNCSPEC: [[BLOCK2]]:
+; FUNCSPEC-NEXT: br label %[[BLOCK3:.*]]
+; FUNCSPEC: [[BLOCK3]]:
+; FUNCSPEC-NEXT: br label %[[EXIT4:.*]]
+; FUNCSPEC: [[EXIT1]]:
+; FUNCSPEC-NEXT: ret i32 [[X]]
+; FUNCSPEC: [[EXIT4]]:
+; FUNCSPEC-NEXT: ret i32 999
+;
+;
+; FUNCSPEC-LABEL: define internal i32 @test_ssa_copy.specialized.1(
+; FUNCSPEC-SAME: i32 [[X:%.*]]) {
+; FUNCSPEC-NEXT: [[ENTRY:.*:]]
+; FUNCSPEC-NEXT: br label %[[BLOCK1:.*]]
+; FUNCSPEC: [[BLOCK1]]:
+; FUNCSPEC-NEXT: br label %[[BLOCK2:.*]]
+; FUNCSPEC: [[BLOCK2]]:
+; FUNCSPEC-NEXT: br label %[[BLOCK3:.*]]
+; FUNCSPEC: [[BLOCK3]]:
+; FUNCSPEC-NEXT: br label %[[EXIT4:.*]]
+; FUNCSPEC: [[EXIT4]]:
+; FUNCSPEC-NEXT: ret i32 poison
+;
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