[llvm] 80c643c - [SystemZ][z/OS] Save (and restore) R3 to avoid clobbering parameter when call stack frame extension is invoked
Neumann Hon via llvm-commits
llvm-commits at lists.llvm.org
Fri May 12 06:34:19 PDT 2023
Author: Neumann Hon
Date: 2023-05-12T09:32:04-04:00
New Revision: 80c643c46422e2af165aacf5d556604b118598b8
URL: https://github.com/llvm/llvm-project/commit/80c643c46422e2af165aacf5d556604b118598b8
DIFF: https://github.com/llvm/llvm-project/commit/80c643c46422e2af165aacf5d556604b118598b8.diff
LOG: [SystemZ][z/OS] Save (and restore) R3 to avoid clobbering parameter when call stack frame extension is invoked
When the stack frame extension routine is used, the contents of r3 is overwritten.
However, if r3 is live in the prologue (ie. one of the function's parameters
resides in r3), it needs to be saved. We save r3 in r0 if r0 is available
(ie. r0 is not used as temporary storage for r4), and in the corresponding
stack slot for the third parameter otherwise.
Differential Revision: https://reviews.llvm.org/D150332
Reviewed By: uweigand
Added:
Modified:
llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
index d7a2a51d4652f..11a59df899a1a 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -1315,6 +1315,10 @@ void SystemZXPLINKFrameLowering::inlineStackProbe(
if (StackAllocMI == nullptr)
return;
+ bool NeedSaveSP = hasFP(MF);
+ bool NeedSaveArg = PrologMBB.isLiveIn(SystemZ::R3D);
+ const int64_t SaveSlotR3 = 2192;
+
MachineBasicBlock &MBB = PrologMBB;
const DebugLoc DL = StackAllocMI->getDebugLoc();
@@ -1334,7 +1338,25 @@ void SystemZXPLINKFrameLowering::inlineStackProbe(
// BASR r3,r3
BuildMI(StackExtMBB, DL, ZII->get(SystemZ::CallBASR_STACKEXT))
.addReg(SystemZ::R3D);
-
+ if (NeedSaveArg) {
+ if (!NeedSaveSP) {
+ // LGR r0,r3
+ BuildMI(MBB, StackAllocMI, DL, ZII->get(SystemZ::LGR))
+ .addReg(SystemZ::R0D, RegState::Define)
+ .addReg(SystemZ::R3D);
+ } else {
+ // In this case, the incoming value of r4 is saved in r0 so the
+ // latter register is unavailable. Store r3 in its corresponding
+ // slot in the parameter list instead. Do this at the start of
+ // the prolog before r4 is manipulated by anything else.
+ // STG r3, 2192(r4)
+ BuildMI(MBB, MBB.begin(), DL, ZII->get(SystemZ::STG))
+ .addReg(SystemZ::R3D)
+ .addReg(SystemZ::R4D)
+ .addImm(SaveSlotR3)
+ .addReg(0);
+ }
+ }
// LLGT r3,1208
BuildMI(MBB, StackAllocMI, DL, ZII->get(SystemZ::LLGT), SystemZ::R3D)
.addReg(0)
@@ -1355,6 +1377,28 @@ void SystemZXPLINKFrameLowering::inlineStackProbe(
NextMBB = SystemZ::splitBlockBefore(StackAllocMI, &MBB);
MBB.addSuccessor(NextMBB);
MBB.addSuccessor(StackExtMBB);
+ if (NeedSaveArg) {
+ if (!NeedSaveSP) {
+ // LGR r3, r0
+ BuildMI(*NextMBB, StackAllocMI, DL, ZII->get(SystemZ::LGR))
+ .addReg(SystemZ::R3D, RegState::Define)
+ .addReg(SystemZ::R0D, RegState::Kill);
+ } else {
+ // In this case, the incoming value of r4 is saved in r0 so the
+ // latter register is unavailable. We stored r3 in its corresponding
+ // slot in the parameter list instead and we now restore it from there.
+ // LGR r3, r0
+ BuildMI(*NextMBB, StackAllocMI, DL, ZII->get(SystemZ::LGR))
+ .addReg(SystemZ::R3D, RegState::Define)
+ .addReg(SystemZ::R0D);
+ // LG r3, 2192(r3)
+ BuildMI(*NextMBB, StackAllocMI, DL, ZII->get(SystemZ::LG))
+ .addReg(SystemZ::R3D, RegState::Define)
+ .addReg(SystemZ::R3D)
+ .addImm(SaveSlotR3)
+ .addReg(0);
+ }
+ }
// Add jump back from stack extension BB.
BuildMI(StackExtMBB, DL, ZII->get(SystemZ::J)).addMBB(NextMBB);
diff --git a/llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll b/llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll
index f074a26481099..13224c01ca9a1 100644
--- a/llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll
+++ b/llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll
@@ -319,12 +319,57 @@ define i64 @func5(i64 %n) {
; CHECK64: lg 3, 72(3)
; CHECK64: basr 3, 3
; CHECK64: stmg 6, 7, 2064(4)
-define void @large_stack() {
+define void @large_stack0() {
%arr = alloca [131072 x i64], align 8
call i64 (ptr) @fun1(ptr %arr)
ret void
}
+; CHECK-LABEL: large_stack1
+; CHECK64: agfi 4, -1048768
+; CHECK64: lgr 0, 3
+; CHECK64: llgt 3, 1208
+; CHECK64: cg 4, 64(3)
+; CHECK64: jhe @BB7_2
+; CHECK64: %bb.1:
+; CHECK64: lg 3, 72(3)
+; CHECK64: basr 3, 3
+; CHECK64: bcr 0, 7
+; CHECK64: @BB7_2:
+; CHECK64: stmg 6, 7, 2064(4)
+; CHECK64: lgr 3, 0
+define void @large_stack1(i64 %n1, i64 %n2, i64 %n3) {
+ %arr = alloca [131072 x i64], align 8
+ call i64 (ptr, i64, i64, i64) @fun3(ptr %arr,
+ i64 %n1, i64 %n2, i64 %n3)
+ ret void
+}
+
+
+; CHECK-LABEL: large_stack2
+; CHECK64: lgr 0, 4
+; CHECK64: stg 3, 2192(4)
+; CHECK64: agfi 4, -1048768
+; CHECK64: llgt 3, 1208
+; CHECK64: cg 4, 64(3)
+; CHECK64: jhe @BB8_2
+; CHECK64: %bb.1:
+; CHECK64: lg 3, 72(3)
+; CHECK64: basr 3, 3
+; CHECK64: bcr 0, 7
+; CHECK64: @BB8_2:
+; CHECK64: lgr 3, 0
+; CHECK64: lg 3, 2192(3)
+; CHECK64: stmg 4, 11, 2048(4)
+; CHECK64: lgr 8, 4
+define void @large_stack2(i64 %n1, i64 %n2, i64 %n3) {
+ %arr0 = alloca [131072 x i64], align 8
+ %arr1 = alloca i64, i64 %n1, align 8
+ call i64 (ptr, ptr, i64, i64, i64) @fun4(ptr %arr0,
+ ptr %arr1, i64 %n1, i64 %n2, i64 %n3)
+ ret void
+}
+
; CHECK-LABEL: leaf_func
; CHECK-NOT: aghi 4,
; CHECK-NOT: stmg
@@ -343,3 +388,5 @@ define i64 @leaf_func0(i64 %a, i64 %b, i64 %c) {
declare i64 @fun(i64 %arg0)
declare i64 @fun1(ptr %ptr)
declare i64 @fun2(i64 %n, ptr %arr0, ptr %arr1)
+declare i64 @fun3(ptr %ptr, i64 %n1, i64 %n2, i64 %n3)
+declare i64 @fun4(ptr %ptr0, ptr %ptr1, i64 %n1, i64 %n2, i64 %n3)
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