[llvm] 42725ae - Process gep (select ptr1, ptr2) in SROA
Stanislav Mekhanoshin via llvm-commits
llvm-commits at lists.llvm.org
Tue May 26 12:56:12 PDT 2020
Author: Stanislav Mekhanoshin
Date: 2020-05-26T12:56:02-07:00
New Revision: 42725aeed8cbabc15e351e2854ae549df2c5dcde
URL: https://github.com/llvm/llvm-project/commit/42725aeed8cbabc15e351e2854ae549df2c5dcde
DIFF: https://github.com/llvm/llvm-project/commit/42725aeed8cbabc15e351e2854ae549df2c5dcde.diff
LOG: Process gep (select ptr1, ptr2) in SROA
Differential Revision: https://reviews.llvm.org/D79217
Added:
llvm/test/Transforms/SROA/select-gep.ll
Modified:
llvm/lib/Transforms/Scalar/SROA.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index 016de041b2f8..1d486a3e74fd 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -3441,7 +3441,58 @@ class AggLoadStoreRewriter : public InstVisitor<AggLoadStoreRewriter, bool> {
return false;
}
+ // Fold gep (select cond, ptr1, ptr2) => select cond, gep(ptr1), gep(ptr2)
+ bool foldGEPSelect(GetElementPtrInst &GEPI) {
+ if (!GEPI.hasAllConstantIndices())
+ return false;
+
+ SelectInst *Sel = cast<SelectInst>(GEPI.getPointerOperand());
+
+ LLVM_DEBUG(dbgs() << " Rewriting gep(select) -> select(gep):"
+ << "\n original: " << *Sel
+ << "\n " << GEPI);
+
+ IRBuilderTy Builder(&GEPI);
+ SmallVector<Value *, 4> Index(GEPI.idx_begin(), GEPI.idx_end());
+ bool IsInBounds = GEPI.isInBounds();
+
+ Value *True = Sel->getTrueValue();
+ Value *NTrue =
+ IsInBounds
+ ? Builder.CreateInBoundsGEP(True, Index,
+ True->getName() + ".sroa.gep")
+ : Builder.CreateGEP(True, Index, True->getName() + ".sroa.gep");
+
+ Value *False = Sel->getFalseValue();
+
+ Value *NFalse =
+ IsInBounds
+ ? Builder.CreateInBoundsGEP(False, Index,
+ False->getName() + ".sroa.gep")
+ : Builder.CreateGEP(False, Index, False->getName() + ".sroa.gep");
+
+ Value *NSel = Builder.CreateSelect(Sel->getCondition(), NTrue, NFalse,
+ Sel->getName() + ".sroa.sel");
+ GEPI.replaceAllUsesWith(NSel);
+ GEPI.eraseFromParent();
+
+ LLVM_DEBUG(dbgs() << "\n to: " << *NTrue
+ << "\n " << *NFalse
+ << "\n " << *NSel << '\n');
+
+ if (isa<Instruction>(NTrue))
+ visit(cast<Instruction>(NTrue));
+ if (isa<Instruction>(NFalse))
+ visit(cast<Instruction>(NFalse));
+
+ return true;
+ }
+
bool visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+ if (isa<SelectInst>(GEPI.getPointerOperand()) &&
+ foldGEPSelect(GEPI))
+ return true;
+
enqueueUsers(GEPI);
return false;
}
diff --git a/llvm/test/Transforms/SROA/select-gep.ll b/llvm/test/Transforms/SROA/select-gep.ll
new file mode 100644
index 000000000000..93cb3420d0af
--- /dev/null
+++ b/llvm/test/Transforms/SROA/select-gep.ll
@@ -0,0 +1,149 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -sroa < %s | FileCheck %s
+
+%pair = type { i32, i32 }
+
+define i32 @test_sroa_select_gep(i1 %cond) {
+; CHECK-LABEL: @test_sroa_select_gep(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[LOAD_SROA_SPECULATED:%.*]] = select i1 [[COND:%.*]], i32 1, i32 2
+; CHECK-NEXT: ret i32 [[LOAD_SROA_SPECULATED]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %b = alloca %pair, align 4
+ %gep_a = getelementptr inbounds %pair, %pair* %a, i32 0, i32 1
+ %gep_b = getelementptr inbounds %pair, %pair* %b, i32 0, i32 1
+ store i32 1, i32* %gep_a, align 4
+ store i32 2, i32* %gep_b, align 4
+ %select = select i1 %cond, %pair* %a, %pair* %b
+ %gep = getelementptr inbounds %pair, %pair* %select, i32 0, i32 1
+ %load = load i32, i32* %gep, align 4
+ ret i32 %load
+}
+
+define i32 @test_sroa_select_gep_non_inbound(i1 %cond) {
+; CHECK-LABEL: @test_sroa_select_gep_non_inbound(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[LOAD_SROA_SPECULATED:%.*]] = select i1 [[COND:%.*]], i32 1, i32 2
+; CHECK-NEXT: ret i32 [[LOAD_SROA_SPECULATED]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %b = alloca %pair, align 4
+ %gep_a = getelementptr %pair, %pair* %a, i32 0, i32 1
+ %gep_b = getelementptr %pair, %pair* %b, i32 0, i32 1
+ store i32 1, i32* %gep_a, align 4
+ store i32 2, i32* %gep_b, align 4
+ %select = select i1 %cond, %pair* %a, %pair* %b
+ %gep = getelementptr %pair, %pair* %select, i32 0, i32 1
+ %load = load i32, i32* %gep, align 4
+ ret i32 %load
+}
+
+define i32 @test_sroa_select_gep_volatile_load(i1 %cond) {
+; CHECK-LABEL: @test_sroa_select_gep_volatile_load(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[A_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[A_SROA_2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B_SROA_2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: store i32 11, i32* [[A_SROA_0]], align 4
+; CHECK-NEXT: store i32 12, i32* [[B_SROA_0]], align 4
+; CHECK-NEXT: store i32 21, i32* [[A_SROA_2]], align 4
+; CHECK-NEXT: store i32 22, i32* [[B_SROA_2]], align 4
+; CHECK-NEXT: [[SELECT_SROA_SEL:%.*]] = select i1 [[COND:%.*]], i32* [[A_SROA_0]], i32* [[B_SROA_0]]
+; CHECK-NEXT: [[LOAD1:%.*]] = load volatile i32, i32* [[SELECT_SROA_SEL]], align 4
+; CHECK-NEXT: [[SELECT_SROA_SEL3:%.*]] = select i1 [[COND]], i32* [[A_SROA_2]], i32* [[B_SROA_2]]
+; CHECK-NEXT: [[LOAD2:%.*]] = load volatile i32, i32* [[SELECT_SROA_SEL3]], align 4
+; CHECK-NEXT: [[ADD:%.*]] = add i32 [[LOAD1]], [[LOAD2]]
+; CHECK-NEXT: ret i32 [[ADD]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %b = alloca %pair, align 4
+ %gep_a0 = getelementptr inbounds %pair, %pair* %a, i32 0, i32 0
+ %gep_b0 = getelementptr inbounds %pair, %pair* %b, i32 0, i32 0
+ store i32 11, i32* %gep_a0, align 4
+ store i32 12, i32* %gep_b0, align 4
+ %gep_a1 = getelementptr inbounds %pair, %pair* %a, i32 0, i32 1
+ %gep_b1 = getelementptr inbounds %pair, %pair* %b, i32 0, i32 1
+ store i32 21, i32* %gep_a1, align 4
+ store i32 22, i32* %gep_b1, align 4
+ %select = select i1 %cond, %pair* %a, %pair* %b
+ %gep1 = getelementptr inbounds %pair, %pair* %select, i32 0, i32 0
+ %load1 = load volatile i32, i32* %gep1, align 4
+ %gep2 = getelementptr inbounds %pair, %pair* %select, i32 0, i32 1
+ %load2 = load volatile i32, i32* %gep2, align 4
+ %add = add i32 %load1, %load2
+ ret i32 %add
+}
+
+define i32 @test_sroa_select_gep_undef(i1 %cond) {
+; CHECK-LABEL: @test_sroa_select_gep_undef(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[A_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[SELECT_SROA_SEL:%.*]] = select i1 [[COND:%.*]], i32* [[A_SROA_0]], i32* undef
+; CHECK-NEXT: [[LOAD:%.*]] = load i32, i32* [[SELECT_SROA_SEL]], align 4
+; CHECK-NEXT: ret i32 [[LOAD]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %select = select i1 %cond, %pair* %a, %pair* undef
+ %gep = getelementptr inbounds %pair, %pair* %select, i32 0, i32 1
+ %load = load i32, i32* %gep, align 4
+ ret i32 %load
+}
+
+define i32 @test_sroa_gep_select_gep(i1 %cond) {
+; CHECK-LABEL: @test_sroa_gep_select_gep(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[A_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: store i32 1, i32* [[A_SROA_0]], align 4
+; CHECK-NEXT: store i32 2, i32* [[B_SROA_0]], align 4
+; CHECK-NEXT: [[SELECT_SROA_SEL:%.*]] = select i1 [[COND:%.*]], i32* [[A_SROA_0]], i32* [[B_SROA_0]]
+; CHECK-NEXT: [[SELECT2:%.*]] = select i1 [[COND]], i32* [[SELECT_SROA_SEL]], i32* [[A_SROA_0]]
+; CHECK-NEXT: [[LOAD:%.*]] = load i32, i32* [[SELECT2]], align 4
+; CHECK-NEXT: ret i32 [[LOAD]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %b = alloca %pair, align 4
+ %gep_a = getelementptr inbounds %pair, %pair* %a, i32 0, i32 1
+ %gep_b = getelementptr inbounds %pair, %pair* %b, i32 0, i32 1
+ store i32 1, i32* %gep_a, align 4
+ store i32 2, i32* %gep_b, align 4
+ %select = select i1 %cond, i32* %gep_a, i32* %gep_b
+ %gep = getelementptr inbounds i32, i32* %select, i32 0
+ %select2 = select i1 %cond, i32* %gep, i32* %gep_a
+ %load = load i32, i32* %select2, align 4
+ ret i32 %load
+}
+
+define i32 @test_sroa_gep_select_gep_nonconst_idx(i1 %cond, i32 %idx) {
+; CHECK-LABEL: @test_sroa_gep_select_gep_nonconst_idx(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[A:%.*]] = alloca [[PAIR:%.*]], align 4
+; CHECK-NEXT: [[B:%.*]] = alloca [[PAIR]], align 4
+; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[A]], i32 0, i32 1
+; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[B]], i32 0, i32 1
+; CHECK-NEXT: store i32 1, i32* [[GEP_A]], align 4
+; CHECK-NEXT: store i32 2, i32* [[GEP_B]], align 4
+; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND:%.*]], %pair* [[A]], %pair* [[B]]
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[SELECT]], i32 [[IDX:%.*]], i32 1
+; CHECK-NEXT: [[LOAD:%.*]] = load i32, i32* [[GEP]], align 4
+; CHECK-NEXT: ret i32 [[LOAD]]
+;
+bb:
+ %a = alloca %pair, align 4
+ %b = alloca %pair, align 4
+ %gep_a = getelementptr inbounds %pair, %pair* %a, i32 0, i32 1
+ %gep_b = getelementptr inbounds %pair, %pair* %b, i32 0, i32 1
+ store i32 1, i32* %gep_a, align 4
+ store i32 2, i32* %gep_b, align 4
+ %select = select i1 %cond, %pair* %a, %pair* %b
+ %gep = getelementptr inbounds %pair, %pair* %select, i32 %idx, i32 1
+ %load = load i32, i32* %gep, align 4
+ ret i32 %load
+}
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