[llvm] [SelectionDAG] Add `STRICT_BF16_TO_FP` and `STRICT_FP_TO_BF16` (PR #80056)

[Matt Arsenault via llvm-commits]

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@@ -1094,11 +1094,52 @@ define <4 x i1> @isnan_v4bf16(<4 x bfloat> %x) nounwind {
   ret <4 x i1> %1
 }
 
-; FIXME: Broken for gfx6/7
-; define i1 @isnan_bf16_strictfp(bfloat %x) strictfp nounwind {
-;   %1 = call i1 @llvm.is.fpclass.bf16(bfloat %x, i32 3) strictfp ; nan
-;   ret i1 %1
-; }
+define i1 @isnan_bf16_strictfp(bfloat %x) strictfp nounwind {
+ ; GFX7CHECK-LABEL: isnan_bf16_strictfp:
+ ; GFX7CHECK:       ; %bb.0:
+ ; GFX7CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+ ; GFX7CHECK-NEXT:    v_bfe_u32 v0, v0, 16, 15
+ ; GFX7CHECK-NEXT:    s_movk_i32 s4, 0x7f80
+ ; GFX7CHECK-NEXT:    v_cmp_lt_i32_e32 vcc, s4, v0
+ ; GFX7CHECK-NEXT:    v_cndmask_b32_e64 v0, 0, 1, vcc
+ ; GFX7CHECK-NEXT:    s_setpc_b64 s[30:31]
+ ;
+ ; GFX8CHECK-LABEL: isnan_bf16_strictfp:
+ ; GFX8CHECK:       ; %bb.0:
+ ; GFX8CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+ ; GFX8CHECK-NEXT:    v_and_b32_e32 v0, 0x7fff, v0
+ ; GFX8CHECK-NEXT:    s_movk_i32 s4, 0x7f80
+ ; GFX8CHECK-NEXT:    v_cmp_lt_i16_e32 vcc, s4, v0
+ ; GFX8CHECK-NEXT:    v_cndmask_b32_e64 v0, 0, 1, vcc
+ ; GFX8CHECK-NEXT:    s_setpc_b64 s[30:31]
+ ;
+ ; GFX9CHECK-LABEL: isnan_bf16_strictfp:
+ ; GFX9CHECK:       ; %bb.0:
+ ; GFX9CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+ ; GFX9CHECK-NEXT:    v_and_b32_e32 v0, 0x7fff, v0
+ ; GFX9CHECK-NEXT:    s_movk_i32 s4, 0x7f80
+ ; GFX9CHECK-NEXT:    v_cmp_lt_i16_e32 vcc, s4, v0
+ ; GFX9CHECK-NEXT:    v_cndmask_b32_e64 v0, 0, 1, vcc
+ ; GFX9CHECK-NEXT:    s_setpc_b64 s[30:31]
+ ;
+ ; GFX10CHECK-LABEL: isnan_bf16_strictfp:
+ ; GFX10CHECK:       ; %bb.0:
+ ; GFX10CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+ ; GFX10CHECK-NEXT:    v_and_b32_e32 v0, 0x7fff, v0
+ ; GFX10CHECK-NEXT:    v_cmp_lt_i16_e32 vcc_lo, 0x7f80, v0
+ ; GFX10CHECK-NEXT:    v_cndmask_b32_e64 v0, 0, 1, vcc_lo
+ ; GFX10CHECK-NEXT:    s_setpc_b64 s[30:31]
+ ;
+ ; GFX11CHECK-LABEL: isnan_bf16_strictfp:
+ ; GFX11CHECK:       ; %bb.0:
+ ; GFX11CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+ ; GFX11CHECK-NEXT:    v_and_b32_e32 v0, 0x7fff, v0
+ ; GFX11CHECK-NEXT:    v_cmp_lt_i16_e32 vcc_lo, 0x7f80, v0
+ ; GFX11CHECK-NEXT:    v_cndmask_b32_e64 v0, 0, 1, vcc_lo
+ ; GFX11CHECK-NEXT:    s_setpc_b64 s[30:31]
+   %1 = call i1 @llvm.is.fpclass.bf16(bfloat %x, i32 3) strictfp ; nan
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arsenm wrote:

don't need the strictfp callsite attribute 

https://github.com/llvm/llvm-project/pull/80056