[llvm] [SDAG] Intersect poison-generating flags after CSE (PR #97434)

Yingwei Zheng via llvm-commits llvm-commits at lists.llvm.org
Wed Jul 3 01:07:11 PDT 2024


https://github.com/dtcxzyw updated https://github.com/llvm/llvm-project/pull/97434

>From a9198b8a06ff0393e0b1cbfcecdc876925c0d239 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Tue, 2 Jul 2024 23:36:35 +0800
Subject: [PATCH 1/4] [SDAG] Add pre-commit tests from PR96366. NFC.

---
 llvm/test/CodeGen/AArch64/pr96366.ll | 23 +++++++++++++++++++++++
 llvm/test/CodeGen/RISCV/pr96366.ll   | 25 +++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/pr96366.ll
 create mode 100644 llvm/test/CodeGen/RISCV/pr96366.ll

diff --git a/llvm/test/CodeGen/AArch64/pr96366.ll b/llvm/test/CodeGen/AArch64/pr96366.ll
new file mode 100644
index 0000000000000..fd13197ca396f
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/pr96366.ll
@@ -0,0 +1,23 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=aarch64 | FileCheck %s
+
+declare void @mumble(i32)
+
+define i32 @f(i32 %0) nounwind {
+; CHECK-LABEL: f:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; CHECK-NEXT:    mov w0, wzr
+; CHECK-NEXT:    bl mumble
+; CHECK-NEXT:    mov w0, #4 // =0x4
+; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    ret
+  %2 = sub nuw i32 0, %0
+  call void @mumble(i32 %2)
+  %3 = sub i32 1, %0
+  %4 = sub i32 3, %0
+  %5 = mul i32 %0, 1
+  %6 = add i32 %3, %5
+  %7 = add i32 %6, %4
+  ret i32 %7
+}
diff --git a/llvm/test/CodeGen/RISCV/pr96366.ll b/llvm/test/CodeGen/RISCV/pr96366.ll
new file mode 100644
index 0000000000000..712d07b3599e0
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/pr96366.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=riscv64 | FileCheck %s
+
+declare void @mumble(i32)
+
+define i32 @f(i32 %0) nounwind {
+; CHECK-LABEL: f:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi sp, sp, -16
+; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    li a0, 0
+; CHECK-NEXT:    call mumble
+; CHECK-NEXT:    li a0, 4
+; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
+; CHECK-NEXT:    addi sp, sp, 16
+; CHECK-NEXT:    ret
+  %2 = sub nuw i32 0, %0
+  call void @mumble(i32 %2)
+  %3 = sub i32 1, %0
+  %4 = sub i32 3, %0
+  %5 = mul i32 %0, 1
+  %6 = add i32 %3, %5
+  %7 = add i32 %6, %4
+  ret i32 %7
+}

>From 10d216a51ed8eff6a9c57f3a5907853407090aa4 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Tue, 2 Jul 2024 23:44:16 +0800
Subject: [PATCH 2/4] [SDAG] Intersect poison-generating flags after CSE

---
 llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp |  1 +
 llvm/test/CodeGen/AArch64/pr96366.ll           | 10 ++++++----
 llvm/test/CodeGen/RISCV/pr96366.ll             |  6 +++++-
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index bc16f885f6a04..96242305e9eab 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1239,6 +1239,7 @@ SelectionDAG::AddModifiedNodeToCSEMaps(SDNode *N) {
       // If there was already an existing matching node, use ReplaceAllUsesWith
       // to replace the dead one with the existing one.  This can cause
       // recursive merging of other unrelated nodes down the line.
+      Existing->intersectFlagsWith(N->getFlags());
       ReplaceAllUsesWith(N, Existing);
 
       // N is now dead. Inform the listeners and delete it.
diff --git a/llvm/test/CodeGen/AArch64/pr96366.ll b/llvm/test/CodeGen/AArch64/pr96366.ll
index fd13197ca396f..392b7b66b0bb1 100644
--- a/llvm/test/CodeGen/AArch64/pr96366.ll
+++ b/llvm/test/CodeGen/AArch64/pr96366.ll
@@ -6,11 +6,13 @@ declare void @mumble(i32)
 define i32 @f(i32 %0) nounwind {
 ; CHECK-LABEL: f:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
-; CHECK-NEXT:    mov w0, wzr
+; CHECK-NEXT:    stp x30, x19, [sp, #-16]! // 16-byte Folded Spill
+; CHECK-NEXT:    mov w19, w0
+; CHECK-NEXT:    neg w0, w0
 ; CHECK-NEXT:    bl mumble
-; CHECK-NEXT:    mov w0, #4 // =0x4
-; CHECK-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; CHECK-NEXT:    mov w8, #4 // =0x4
+; CHECK-NEXT:    sub w0, w8, w19
+; CHECK-NEXT:    ldp x30, x19, [sp], #16 // 16-byte Folded Reload
 ; CHECK-NEXT:    ret
   %2 = sub nuw i32 0, %0
   call void @mumble(i32 %2)
diff --git a/llvm/test/CodeGen/RISCV/pr96366.ll b/llvm/test/CodeGen/RISCV/pr96366.ll
index 712d07b3599e0..05563d7bc14af 100644
--- a/llvm/test/CodeGen/RISCV/pr96366.ll
+++ b/llvm/test/CodeGen/RISCV/pr96366.ll
@@ -8,10 +8,14 @@ define i32 @f(i32 %0) nounwind {
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    addi sp, sp, -16
 ; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
-; CHECK-NEXT:    li a0, 0
+; CHECK-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    mv s0, a0
+; CHECK-NEXT:    negw a0, a0
 ; CHECK-NEXT:    call mumble
 ; CHECK-NEXT:    li a0, 4
+; CHECK-NEXT:    subw a0, a0, s0
 ; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
+; CHECK-NEXT:    ld s0, 0(sp) # 8-byte Folded Reload
 ; CHECK-NEXT:    addi sp, sp, 16
 ; CHECK-NEXT:    ret
   %2 = sub nuw i32 0, %0

>From 1108057d2c990ebe68fa7afe87bcb5953a289da1 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Wed, 3 Jul 2024 01:19:08 +0800
Subject: [PATCH 3/4] [SDAG] Address review comments. NFC.

---
 llvm/test/CodeGen/AArch64/pr96366.ll | 22 +++++++++++-----------
 llvm/test/CodeGen/RISCV/pr96366.ll   | 22 +++++++++++-----------
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/llvm/test/CodeGen/AArch64/pr96366.ll b/llvm/test/CodeGen/AArch64/pr96366.ll
index 392b7b66b0bb1..0a5d87c7f9bbf 100644
--- a/llvm/test/CodeGen/AArch64/pr96366.ll
+++ b/llvm/test/CodeGen/AArch64/pr96366.ll
@@ -1,25 +1,25 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc < %s -mtriple=aarch64 | FileCheck %s
 
-declare void @mumble(i32)
+declare void @use(i32)
 
-define i32 @f(i32 %0) nounwind {
+define i32 @f(i32 %x) nounwind {
 ; CHECK-LABEL: f:
 ; CHECK:       // %bb.0:
 ; CHECK-NEXT:    stp x30, x19, [sp, #-16]! // 16-byte Folded Spill
 ; CHECK-NEXT:    mov w19, w0
 ; CHECK-NEXT:    neg w0, w0
-; CHECK-NEXT:    bl mumble
+; CHECK-NEXT:    bl use
 ; CHECK-NEXT:    mov w8, #4 // =0x4
 ; CHECK-NEXT:    sub w0, w8, w19
 ; CHECK-NEXT:    ldp x30, x19, [sp], #16 // 16-byte Folded Reload
 ; CHECK-NEXT:    ret
-  %2 = sub nuw i32 0, %0
-  call void @mumble(i32 %2)
-  %3 = sub i32 1, %0
-  %4 = sub i32 3, %0
-  %5 = mul i32 %0, 1
-  %6 = add i32 %3, %5
-  %7 = add i32 %6, %4
-  ret i32 %7
+  %sub1 = sub nuw i32 0, %x
+  call void @use(i32 %sub1)
+  %sub2 = sub i32 1, %x
+  %sub3 = sub i32 3, %x
+  %mul = mul i32 %x, 1
+  %add1 = add i32 %sub2, %mul
+  %add2 = add i32 %add1, %sub3
+  ret i32 %add2
 }
diff --git a/llvm/test/CodeGen/RISCV/pr96366.ll b/llvm/test/CodeGen/RISCV/pr96366.ll
index 05563d7bc14af..8c6fd5bfb6cb0 100644
--- a/llvm/test/CodeGen/RISCV/pr96366.ll
+++ b/llvm/test/CodeGen/RISCV/pr96366.ll
@@ -1,9 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc < %s -mtriple=riscv64 | FileCheck %s
 
-declare void @mumble(i32)
+declare void @use(i32)
 
-define i32 @f(i32 %0) nounwind {
+define i32 @f(i32 %x) nounwind {
 ; CHECK-LABEL: f:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    addi sp, sp, -16
@@ -11,19 +11,19 @@ define i32 @f(i32 %0) nounwind {
 ; CHECK-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
 ; CHECK-NEXT:    mv s0, a0
 ; CHECK-NEXT:    negw a0, a0
-; CHECK-NEXT:    call mumble
+; CHECK-NEXT:    call use
 ; CHECK-NEXT:    li a0, 4
 ; CHECK-NEXT:    subw a0, a0, s0
 ; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
 ; CHECK-NEXT:    ld s0, 0(sp) # 8-byte Folded Reload
 ; CHECK-NEXT:    addi sp, sp, 16
 ; CHECK-NEXT:    ret
-  %2 = sub nuw i32 0, %0
-  call void @mumble(i32 %2)
-  %3 = sub i32 1, %0
-  %4 = sub i32 3, %0
-  %5 = mul i32 %0, 1
-  %6 = add i32 %3, %5
-  %7 = add i32 %6, %4
-  ret i32 %7
+  %sub1 = sub nuw i32 0, %x
+  call void @use(i32 %sub1)
+  %sub2 = sub i32 1, %x
+  %sub3 = sub i32 3, %x
+  %mul = mul i32 %x, 1
+  %add1 = add i32 %sub2, %mul
+  %add2 = add i32 %add1, %sub3
+  ret i32 %add2
 }

>From 8bb2460fbe5f25dfc6d9c7717bbb00c7928978d3 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Wed, 3 Jul 2024 16:06:48 +0800
Subject: [PATCH 4/4] [SDAG] Fix tests. NFC.

---
 llvm/test/CodeGen/AMDGPU/dagcombine-fma-crash.ll | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/test/CodeGen/AMDGPU/dagcombine-fma-crash.ll b/llvm/test/CodeGen/AMDGPU/dagcombine-fma-crash.ll
index 8b1a6878136a9..ddb635cabbab1 100644
--- a/llvm/test/CodeGen/AMDGPU/dagcombine-fma-crash.ll
+++ b/llvm/test/CodeGen/AMDGPU/dagcombine-fma-crash.ll
@@ -90,7 +90,7 @@ define float @test2(float %arg, float %arg1) {
   ; CHECK-NEXT:   [[S_MOV_B32_:%[0-9]+]]:sgpr_32 = S_MOV_B32 1120534528
   ; CHECK-NEXT:   [[V_FMAC_F32_e64_:%[0-9]+]]:vgpr_32 = nsz contract reassoc nofpexcept V_FMAC_F32_e64 0, [[COPY]], 0, killed [[S_MOV_B32_]], 0, [[V_MOV_B32_e32_]], 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   [[S_MOV_B32_1:%[0-9]+]]:sgpr_32 = S_MOV_B32 0
-  ; CHECK-NEXT:   [[V_FMAC_F32_e64_1:%[0-9]+]]:vgpr_32 = nsz contract reassoc nofpexcept V_FMAC_F32_e64 0, [[COPY1]], 0, killed [[S_MOV_B32_1]], 0, [[V_FMAC_F32_e64_]], 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   [[V_FMAC_F32_e64_1:%[0-9]+]]:vgpr_32 = nsz contract nofpexcept V_FMAC_F32_e64 0, [[COPY1]], 0, killed [[S_MOV_B32_1]], 0, [[V_FMAC_F32_e64_]], 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   [[V_ADD_F32_e64_:%[0-9]+]]:vgpr_32 = nsz contract reassoc nofpexcept V_ADD_F32_e64 0, [[V_FMAC_F32_e64_1]], 0, [[V_MOV_B32_e32_]], 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   [[V_RCP_F32_e64_:%[0-9]+]]:vgpr_32 = nofpexcept V_RCP_F32_e64 0, [[V_FMAC_F32_e64_1]], 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   [[V_RCP_F32_e64_1:%[0-9]+]]:vgpr_32 = nofpexcept V_RCP_F32_e64 0, killed [[V_ADD_F32_e64_]], 0, 0, implicit $mode, implicit $exec



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