[llvm] [AMDGPU] Sign extend simm16 in setreg intrinsic (PR #77997)

[Stanislav Mekhanoshin via llvm-commits]

https://github.com/rampitec created https://github.com/llvm/llvm-project/pull/77997

We currently force users to use a negative contant in the intrinsic call. Changing it zext would break existing programs, so just sign extend an argument.

>From 01af6c9d8e80b810bbdec35dee38b1cf5d73cfe0 Mon Sep 17 00:00:00 2001
From: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
Date: Fri, 12 Jan 2024 15:07:53 -0800
Subject: [PATCH] [AMDGPU] Sign extend simm16 in setreg intrinsic

We currently force users to use a negative contant in the
intrinsic call. Changing it zext would break existing programs,
so just sign extend an argument.
---
 llvm/lib/Target/AMDGPU/SOPInstructions.td     | 11 ++--
 .../CodeGen/AMDGPU/llvm.amdgcn.s.setreg.ll    | 66 +++++++++++++++++++
 2 files changed, 72 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SOPInstructions.td b/llvm/lib/Target/AMDGPU/SOPInstructions.td
index 46fa3d57a21cb2..5b35d4dcac2e4f 100644
--- a/llvm/lib/Target/AMDGPU/SOPInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SOPInstructions.td
@@ -1117,14 +1117,12 @@ def S_GETREG_B32 : SOPK_Pseudo <
 let Defs = [MODE], Uses = [MODE] in {
 
 // FIXME: Need to truncate immediate to 16-bits.
-class S_SETREG_B32_Pseudo <list<dag> pattern=[]> : SOPK_Pseudo <
+class S_SETREG_B32_Pseudo : SOPK_Pseudo <
   "s_setreg_b32",
   (outs), (ins SReg_32:$sdst, hwreg:$simm16),
-  "$simm16, $sdst",
-  pattern>;
+  "$simm16, $sdst">;
 
-def S_SETREG_B32 : S_SETREG_B32_Pseudo <
-  [(int_amdgcn_s_setreg (i32 timm:$simm16), i32:$sdst)]> {
+def S_SETREG_B32 : S_SETREG_B32_Pseudo {
   // Use custom inserter to optimize some cases to
   // S_DENORM_MODE/S_ROUND_MODE/S_SETREG_B32_mode.
   let usesCustomInserter = 1;
@@ -1160,6 +1158,9 @@ def S_SETREG_IMM32_B32_mode : S_SETREG_IMM32_B32_Pseudo {
 
 } // End Defs = [MODE], Uses = [MODE]
 
+def : GCNPat<(int_amdgcn_s_setreg (i32 timm:$simm16), i32:$sdst),
+             (S_SETREG_B32 $sdst, (as_i16timm $simm16))>;
+
 class SOPK_WAITCNT<string opName, list<dag> pat=[]> :
     SOPK_Pseudo<
         opName,
diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.setreg.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.setreg.ll
index d2c14f2401fc35..99d80b5dd14b33 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.setreg.ll
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.setreg.ll
@@ -1433,6 +1433,72 @@ define amdgpu_kernel void @test_setreg_set_4_bits_straddles_round_and_denorm() {
   ret void
 }
 
+define amdgpu_ps void @test_63489(i32 inreg %var.mode) {
+; GFX6-LABEL: test_63489:
+; GFX6:       ; %bb.0:
+; GFX6-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x80,0xb9]
+; GFX6-NEXT:    ;;#ASMSTART
+; GFX6-NEXT:    ;;#ASMEND
+; GFX6-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX789-LABEL: test_63489:
+; GFX789:       ; %bb.0:
+; GFX789-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x00,0xb9]
+; GFX789-NEXT:    ;;#ASMSTART
+; GFX789-NEXT:    ;;#ASMEND
+; GFX789-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX10-LABEL: test_63489:
+; GFX10:       ; %bb.0:
+; GFX10-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x80,0xb9]
+; GFX10-NEXT:    ;;#ASMSTART
+; GFX10-NEXT:    ;;#ASMEND
+; GFX10-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX11-LABEL: test_63489:
+; GFX11:       ; %bb.0:
+; GFX11-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x00,0xb9]
+; GFX11-NEXT:    ;;#ASMSTART
+; GFX11-NEXT:    ;;#ASMEND
+; GFX11-NEXT:    s_endpgm ; encoding: [0x00,0x00,0xb0,0xbf]
+  call void @llvm.amdgcn.s.setreg(i32 63489, i32 %var.mode)
+  call void asm sideeffect "", ""()
+  ret void
+}
+
+define amdgpu_ps void @test_minus_2047(i32 inreg %var.mode) {
+; GFX6-LABEL: test_minus_2047:
+; GFX6:       ; %bb.0:
+; GFX6-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x80,0xb9]
+; GFX6-NEXT:    ;;#ASMSTART
+; GFX6-NEXT:    ;;#ASMEND
+; GFX6-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX789-LABEL: test_minus_2047:
+; GFX789:       ; %bb.0:
+; GFX789-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x00,0xb9]
+; GFX789-NEXT:    ;;#ASMSTART
+; GFX789-NEXT:    ;;#ASMEND
+; GFX789-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX10-LABEL: test_minus_2047:
+; GFX10:       ; %bb.0:
+; GFX10-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x80,0xb9]
+; GFX10-NEXT:    ;;#ASMSTART
+; GFX10-NEXT:    ;;#ASMEND
+; GFX10-NEXT:    s_endpgm ; encoding: [0x00,0x00,0x81,0xbf]
+;
+; GFX11-LABEL: test_minus_2047:
+; GFX11:       ; %bb.0:
+; GFX11-NEXT:    s_setreg_b32 hwreg(HW_REG_MODE), s0 ; encoding: [0x01,0xf8,0x00,0xb9]
+; GFX11-NEXT:    ;;#ASMSTART
+; GFX11-NEXT:    ;;#ASMEND
+; GFX11-NEXT:    s_endpgm ; encoding: [0x00,0x00,0xb0,0xbf]
+  call void @llvm.amdgcn.s.setreg(i32 -2047, i32 %var.mode)
+  call void asm sideeffect "", ""()
+  ret void
+}
+
 ; FIXME: Broken for DAG
 ; define void @test_setreg_roundingmode_var_vgpr(i32 %var.mode) {
 ;   call void @llvm.amdgcn.s.setreg(i32 4097, i32 %var.mode)