[llvm] c6a199f - [NVPTX] Emit pragma nounroll for llvm.loop.unroll.count=1
Dmitry Vassiliev via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 14 16:30:43 PST 2022
Author: Dmitry Vassiliev
Date: 2022-11-15T04:30:00+04:00
New Revision: c6a199fb4fc01892e7c0b15968eb47eb3b4036e3
URL: https://github.com/llvm/llvm-project/commit/c6a199fb4fc01892e7c0b15968eb47eb3b4036e3
DIFF: https://github.com/llvm/llvm-project/commit/c6a199fb4fc01892e7c0b15968eb47eb3b4036e3.diff
LOG: [NVPTX] Emit pragma nounroll for llvm.loop.unroll.count=1
Emit pragma nounroll for llvm.loop.unroll.count=1 (#pragma unroll 1).
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D137991
Added:
Modified:
llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
llvm/test/CodeGen/NVPTX/nounroll.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index 55a3626a30b64..5b0bf57a48f84 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -406,8 +406,7 @@ void NVPTXAsmPrinter::printReturnValStr(const MachineFunction &MF,
}
// Return true if MBB is the header of a loop marked with
-// llvm.loop.unroll.disable.
-// TODO: consider "#pragma unroll 1" which is equivalent to "#pragma nounroll".
+// llvm.loop.unroll.disable or llvm.loop.unroll.count=1.
bool NVPTXAsmPrinter::isLoopHeaderOfNoUnroll(
const MachineBasicBlock &MBB) const {
MachineLoopInfo &LI = getAnalysis<MachineLoopInfo>();
@@ -428,6 +427,12 @@ bool NVPTXAsmPrinter::isLoopHeaderOfNoUnroll(
PBB->getTerminator()->getMetadata(LLVMContext::MD_loop)) {
if (GetUnrollMetadata(LoopID, "llvm.loop.unroll.disable"))
return true;
+ if (MDNode *UnrollCountMD =
+ GetUnrollMetadata(LoopID, "llvm.loop.unroll.count")) {
+ if (mdconst::extract<ConstantInt>(UnrollCountMD->getOperand(1))
+ ->getZExtValue() == 1)
+ return true;
+ }
}
}
}
diff --git a/llvm/test/CodeGen/NVPTX/nounroll.ll b/llvm/test/CodeGen/NVPTX/nounroll.ll
index 474c38f8d85ac..8a42e0f3d0dce 100644
--- a/llvm/test/CodeGen/NVPTX/nounroll.ll
+++ b/llvm/test/CodeGen/NVPTX/nounroll.ll
@@ -34,5 +34,37 @@ for.end:
ret void
}
+; Compiled from the following CUDA code:
+;
+; #pragma unroll 1
+; for (int i = 0; i < 2; ++i)
+; output[i] = input[i];
+define void @unroll1(float* %input, float* %output) {
+; CHECK-LABEL: .visible .func unroll1(
+entry:
+ br label %for.body
+
+for.body:
+; CHECK: .pragma "nounroll"
+ %i.06 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %idxprom = sext i32 %i.06 to i64
+ %arrayidx = getelementptr inbounds float, float* %input, i64 %idxprom
+ %0 = load float, float* %arrayidx, align 4
+; CHECK: ld.f32
+ %arrayidx2 = getelementptr inbounds float, float* %output, i64 %idxprom
+ store float %0, float* %arrayidx2, align 4
+; CHECK: st.f32
+ %inc = add nuw nsw i32 %i.06, 1
+ %exitcond = icmp eq i32 %inc, 2
+ br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !2
+; CHECK-NOT: ld.f32
+; CHECK-NOT: st.f32
+
+for.end:
+ ret void
+}
+
!0 = distinct !{!0, !1}
!1 = !{!"llvm.loop.unroll.disable"}
+!2 = distinct !{!2, !3}
+!3 = !{!"llvm.loop.unroll.count", i32 1}
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