[llvm] Invalidate range metadata when folding bitcast into load (PR #133095)
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Wed Mar 26 19:11:50 PDT 2025
https://github.com/LU-JOHN updated https://github.com/llvm/llvm-project/pull/133095
>From ddcaccbbb9734c26eeff5b61502ec329fed55318 Mon Sep 17 00:00:00 2001
From: John Lu <John.Lu at amd.com>
Date: Wed, 26 Mar 2025 09:31:47 -0500
Subject: [PATCH 1/3] Invalidate range MD, when folding bitcast into load
Signed-off-by: John Lu <John.Lu at amd.com>
---
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 9 ++++++
.../test/CodeGen/X86/fold_bitcast_md_range.ll | 31 +++++++++++++++++++
2 files changed, 40 insertions(+)
create mode 100644 llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index bf49642634291..a8e516b8c2937 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -15964,6 +15964,15 @@ SDValue DAGCombiner::visitBITCAST(SDNode *N) {
if (TLI.isLoadBitCastBeneficial(N0.getValueType(), VT, DAG,
*LN0->getMemOperand())) {
+ // If the range metadata type does not match the new memory
+ // operation type, remove the range metadata.
+ if (const MDNode *MD = LN0->getRanges()) {
+ ConstantInt *Lower = mdconst::extract<ConstantInt>(MD->getOperand(0));
+ if (Lower->getBitWidth() != VT.getScalarSizeInBits() ||
+ !VT.isInteger()) {
+ LN0->getMemOperand()->clearRanges();
+ }
+ }
SDValue Load =
DAG.getLoad(VT, SDLoc(N), LN0->getChain(), LN0->getBasePtr(),
LN0->getMemOperand());
diff --git a/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
new file mode 100644
index 0000000000000..3417acb4e2744
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=x86_64-apple-macosx10.12.0 -O0 < %s | FileCheck %s
+
+; Ensure that when a bitcast is folded into a load, range metadata is invalidated
+; if it does not match the new type.
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+
+define void @fold_bitcast_range_metadata() {
+; CHECK-LABEL: fold_bitcast_range_metadata:
+; CHECK: ## %bb.0: ## %start
+; CHECK-NEXT: movaps 0, %xmm0
+; CHECK-NEXT: movaps {{.*#+}} xmm1 = [1,0,0,0]
+; CHECK-NEXT: pcmpeqb %xmm1, %xmm0
+; CHECK-NEXT: pmovmskb %xmm0, %eax
+; CHECK-NEXT: subl $65535, %eax ## imm = 0xFFFF
+; CHECK-NEXT: jne LBB0_1
+; CHECK-NEXT: jmp LBB0_1
+; CHECK-NEXT: LBB0_1: ## %bb1
+; CHECK-NEXT: retq
+start:
+ %0 = load i128, ptr null, align 16, !range !0, !noundef !1
+ %1 = icmp eq i128 %0, 1
+ br i1 %1, label %bb1, label %bb1
+
+bb1: ; preds = %start, %start
+ ret void
+}
+
+!0 = !{i128 0, i128 3}
+!1 = !{}
>From 3ebec392cac34138d161ca659fca8afb92eb9534 Mon Sep 17 00:00:00 2001
From: John Lu <John.Lu at amd.com>
Date: Wed, 26 Mar 2025 12:14:18 -0500
Subject: [PATCH 2/3] Clean up testcase
Signed-off-by: John Lu <John.Lu at amd.com>
---
.../test/CodeGen/X86/fold_bitcast_md_range.ll | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
index 3417acb4e2744..dea90e0ba5221 100644
--- a/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
+++ b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
@@ -4,27 +4,20 @@
; Ensure that when a bitcast is folded into a load, range metadata is invalidated
; if it does not match the new type.
-target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
-
-define void @fold_bitcast_range_metadata() {
+define i1 @fold_bitcast_range_metadata(ptr %valptr) {
; CHECK-LABEL: fold_bitcast_range_metadata:
; CHECK: ## %bb.0: ## %start
-; CHECK-NEXT: movaps 0, %xmm0
+; CHECK-NEXT: movaps (%rdi), %xmm0
; CHECK-NEXT: movaps {{.*#+}} xmm1 = [1,0,0,0]
; CHECK-NEXT: pcmpeqb %xmm1, %xmm0
; CHECK-NEXT: pmovmskb %xmm0, %eax
; CHECK-NEXT: subl $65535, %eax ## imm = 0xFFFF
-; CHECK-NEXT: jne LBB0_1
-; CHECK-NEXT: jmp LBB0_1
-; CHECK-NEXT: LBB0_1: ## %bb1
+; CHECK-NEXT: sete %al
; CHECK-NEXT: retq
start:
- %0 = load i128, ptr null, align 16, !range !0, !noundef !1
- %1 = icmp eq i128 %0, 1
- br i1 %1, label %bb1, label %bb1
-
-bb1: ; preds = %start, %start
- ret void
+ %val = load i128, ptr %valptr, align 16, !range !0, !noundef !1
+ %bool = icmp eq i128 %val, 1
+ ret i1 %bool
}
!0 = !{i128 0, i128 3}
>From 36bf7750457a61d8dd281b75d3269eb0f7ca47dc Mon Sep 17 00:00:00 2001
From: John Lu <John.Lu at amd.com>
Date: Wed, 26 Mar 2025 21:11:36 -0500
Subject: [PATCH 3/3] -O0 is unnecessary
Signed-off-by: John Lu <John.Lu at amd.com>
---
llvm/test/CodeGen/X86/fold_bitcast_md_range.ll | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
index dea90e0ba5221..88eee984477b2 100644
--- a/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
+++ b/llvm/test/CodeGen/X86/fold_bitcast_md_range.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
-; RUN: llc -mtriple=x86_64-apple-macosx10.12.0 -O0 < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-apple-macosx10.12.0 < %s | FileCheck %s
; Ensure that when a bitcast is folded into a load, range metadata is invalidated
; if it does not match the new type.
@@ -7,11 +7,10 @@
define i1 @fold_bitcast_range_metadata(ptr %valptr) {
; CHECK-LABEL: fold_bitcast_range_metadata:
; CHECK: ## %bb.0: ## %start
-; CHECK-NEXT: movaps (%rdi), %xmm0
-; CHECK-NEXT: movaps {{.*#+}} xmm1 = [1,0,0,0]
-; CHECK-NEXT: pcmpeqb %xmm1, %xmm0
+; CHECK-NEXT: movdqa (%rdi), %xmm0
+; CHECK-NEXT: pcmpeqb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; CHECK-NEXT: pmovmskb %xmm0, %eax
-; CHECK-NEXT: subl $65535, %eax ## imm = 0xFFFF
+; CHECK-NEXT: cmpl $65535, %eax ## imm = 0xFFFF
; CHECK-NEXT: sete %al
; CHECK-NEXT: retq
start:
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