[ARM] Fix expansion of ABS in a call sequence

[jayfoad]

Fixes #147162

[llvmbot]

@llvm/pr-subscribers-backend-arm

Author: Jay Foad (jayfoad)

Changes

Fixes #147162

---

Full diff: https://github.com/llvm/llvm-project/pull/147270.diff

2 Files Affected:

• (modified) llvm/lib/Target/ARM/ARMISelLowering.cpp (+5)
• (modified) llvm/test/CodeGen/ARM/iabs.ll (+25)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index eb3c741c6ded2..5378ca2a485d4 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -12359,6 +12359,11 @@ ARMTargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
     Fn->insert(BBI, RSBBB);
     Fn->insert(BBI, SinkBB);
 
+    // Set the call frame size on entry to the new basic blocks.
+    unsigned CallFrameSize = TII->getCallFrameSizeAt(MI);
+    RSBBB->setCallFrameSize(CallFrameSize);
+    SinkBB->setCallFrameSize(CallFrameSize);
+
     Register ABSSrcReg = MI.getOperand(1).getReg();
     Register ABSDstReg = MI.getOperand(0).getReg();
     bool ABSSrcKIll = MI.getOperand(1).isKill();
diff --git a/llvm/test/CodeGen/ARM/iabs.ll b/llvm/test/CodeGen/ARM/iabs.ll
index fffa9555b2966..758fe7507c0b2 100644
--- a/llvm/test/CodeGen/ARM/iabs.ll
+++ b/llvm/test/CodeGen/ARM/iabs.ll
@@ -50,3 +50,28 @@ define i64 @test3(i64 %a) {
   %abs = select i1 %b, i64 %a, i64 %tmp1neg
   ret i64 %abs
 }
+
+declare void @callee(...)
+
+define void @testcallframe(i32 %a) {
+; CHECK-LABEL: testcallframe:
+; CHECK:       @ %bb.0: @ %bb
+; CHECK-NEXT:    .save {r11, lr}
+; CHECK-NEXT:    push {r11, lr}
+; CHECK-NEXT:    .pad #8
+; CHECK-NEXT:    sub sp, sp, #8
+; CHECK-NEXT:    cmp r0, #0
+; CHECK-NEXT:    mov r1, #0
+; CHECK-NEXT:    rsbmi r0, r0, #0
+; CHECK-NEXT:    mov r2, #0
+; CHECK-NEXT:    mov r3, #0
+; CHECK-NEXT:    str r1, [sp]
+; CHECK-NEXT:    bl callee
+; CHECK-NEXT:    add sp, sp, #8
+; CHECK-NEXT:    pop {r11, lr}
+; CHECK-NEXT:    bx lr
+bb:
+  %i = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+  tail call void @callee(i32 %i, i32 0, i32 0, i32 0, i32 0)
+  ret void
+}

[mstorsjo]

#147195 is another attempt at solving the same issue. Thanks for both fixes! I haven't had time to look at them and I'm probably not qualified to comment on them anyway though.

[davemgreen]

It's a good sign that we wrote the same thing. LGTM