[llvm] [CodeGen] Add preliminary plumbing for `samesign` flag (PR #112354)

[Thorsten Schütt via llvm-commits]

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@@ -0,0 +1,33 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=aarch64-linux-gnu -O0 -stop-after=irtranslator -global-isel -verify-machineinstrs %s -o - 2>&1 | FileCheck %s
+
+define i1 @icmp_samesign(i32 %a, i32 %b) {
+  ; CHECK-LABEL: name: icmp_samesign
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK-NEXT:   liveins: $w0, $w1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:_(s32) = COPY $w1
+  ; CHECK-NEXT:   %2:_(s1) = samesign G_ICMP intpred(ult), [[COPY]](s32), [[COPY1]]
+  ; CHECK-NEXT:   [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT %2(s1)
+  ; CHECK-NEXT:   [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[ZEXT]](s8)
+  ; CHECK-NEXT:   $w0 = COPY [[ANYEXT]](s32)
+  ; CHECK-NEXT:   RET_ReallyLR implicit $w0
+    %res = icmp samesign ult i32 %a, %b
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tschuett wrote:

There is no test without `samesign`.

https://github.com/llvm/llvm-project/pull/112354