[NVPTX] Implement isTruncateFree and isZExtFree for i32/i64 Optimizations #114658
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@llvm/pr-subscribers-backend-nvptx Author: None (Quark-69) ChangesSolves #114339 Implemented the isTruncateFree and isZExtFree virtual functions in the NVPTXTargetLowering class. This implementation optimizes truncation from i64 to i32 and zero-extension from i32 to i64, recognizing that these operations can be considered free in the NVPTX architecture. Details:
Testing:
Full diff: https://github.com/llvm/llvm-project/pull/114658.diff 3 Files Affected:
diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
index d3bf0ecfe2cc92..b5fc975d71dfa8 100644
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -3340,6 +3340,29 @@ bool NVPTXTargetLowering::splitValueIntoRegisterParts(
return false;
}
+bool llvm::NVPTXTargetLowering::isTruncateFree(EVT FromVT, EVT ToVT) const {
+
+ if (!FromVT.isSimple() || !ToVT.isSimple()) {
+ return false;
+ }
+
+ return (FromVT.getSimpleVT() == MVT::i64 && ToVT.getSimpleVT() == MVT::i32);
+}
+
+bool llvm::NVPTXTargetLowering::isZExtFree(EVT FromVT, EVT ToVT) const {
+ if (!FromVT.isSimple() || !ToVT.isSimple()) {
+ return false;
+ }
+ return (FromVT.getSimpleVT() == MVT::i32 && ToVT.getSimpleVT() == MVT::i64);
+}
+
+bool llvm::NVPTXTargetLowering::isZExtFree(Type *SrcTy, Type *DstTy) const {
+ if (!SrcTy->isIntegerTy() || !DstTy->isIntegerTy())
+ return false;
+ return SrcTy->getPrimitiveSizeInBits() == 32 &&
+ DstTy->getPrimitiveSizeInBits() == 64;
+}
+
// This creates target external symbol for a function parameter.
// Name of the symbol is composed from its index and the function name.
// Negative index corresponds to special parameter (unsized array) used for
diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.h b/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
index c8b589ae39413e..fa73938a35a168 100644
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
@@ -616,6 +616,10 @@ class NVPTXTargetLowering : public TargetLowering {
return true;
}
+ bool isTruncateFree(EVT FromVT, EVT ToVT) const override;
+ bool isZExtFree(EVT FromVT, EVT ToVT) const override;
+ bool isZExtFree(Type *SrcTy, Type *DstTy) const override;
+
private:
const NVPTXSubtarget &STI; // cache the subtarget here
SDValue getParamSymbol(SelectionDAG &DAG, int idx, EVT) const;
diff --git a/llvm/test/CodeGen/NVPTX/truncate_zext.ll b/llvm/test/CodeGen/NVPTX/truncate_zext.ll
new file mode 100644
index 00000000000000..decc02c5840491
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/truncate_zext.ll
@@ -0,0 +1,17 @@
+; RUN: llc -march=nvptx64 < %s | FileCheck %s
+
+; Test for truncation from i64 to i32
+define i32 @test_trunc_i64_to_i32(i64 %val) {
+ ; CHECK-LABEL: test_trunc_i64_to_i32
+ ; CHECK: trunc
+ %trunc = trunc i64 %val to i32
+ ret i32 %trunc
+}
+
+; Test for zero-extension from i32 to i64
+define i64 @test_zext_i32_to_i64(i32 %val) {
+ ; CHECK-LABEL: test_zext_i32_to_i64
+ ; CHECK: zext
+ %zext = zext i32 %val to i64
+ ret i64 %zext
+}
\ No newline at end of file
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2 participants
Solves #114339
Implemented the isTruncateFree and isZExtFree virtual functions in the NVPTXTargetLowering class. This implementation optimizes truncation from i64 to i32 and zero-extension from i32 to i64, recognizing that these operations can be considered free in the NVPTX architecture.
Details:
truefor zero-extension from i32 to i64.Testing: