Simple check to ignore Inline asm fwait insertion

[Temperature-block]

Just a simple check to ignore Inline asm fwait insertion

Fixes #101613

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@llvm/pr-subscribers-backend-x86

Author: Temperatureblock (Temperature-block)

Changes

Just a simple check to ignore Inline asm fwait insertion

---

Full diff: https://github.com/llvm/llvm-project/pull/101686.diff

2 Files Affected:

• (modified) llvm/lib/Target/X86/X86InsertWait.cpp (+3-2)
• (modified) llvm/test/CodeGen/X86/pr59305.ll (-3)

diff --git a/llvm/lib/Target/X86/X86InsertWait.cpp b/llvm/lib/Target/X86/X86InsertWait.cpp
index 69a3d32a93149..0a1810a3da711 100644
--- a/llvm/lib/Target/X86/X86InsertWait.cpp
+++ b/llvm/lib/Target/X86/X86InsertWait.cpp
@@ -103,8 +103,9 @@ bool WaitInsert::runOnMachineFunction(MachineFunction &MF) {
 
   for (MachineBasicBlock &MBB : MF) {
     for (MachineBasicBlock::iterator MI = MBB.begin(); MI != MBB.end(); ++MI) {
-      // Jump non X87 instruction.
-      if (!X86::isX87Instruction(*MI))
+
+      // Jump non X87 instruction and Inline asm.
+      if (!X86::isX87Instruction(*MI) || MI->isInlineAsm())
         continue;
       // If the instruction instruction neither has float exception nor is
       // a load/store instruction, or the instruction is x87 control
diff --git a/llvm/test/CodeGen/X86/pr59305.ll b/llvm/test/CodeGen/X86/pr59305.ll
index 46c9da5a51939..5185f1429f289 100644
--- a/llvm/test/CodeGen/X86/pr59305.ll
+++ b/llvm/test/CodeGen/X86/pr59305.ll
@@ -81,20 +81,17 @@ define double @bar(double %0) #0 {
 ; X64-NEXT:    #APP
 ; X64-NEXT:    ldmxcsr 0
 ; X64-NEXT:    #NO_APP
-; X64-NEXT:    wait
 ; X64-NEXT:    movsd {{.*#+}} xmm2 = [1.0E+0,0.0E+0]
 ; X64-NEXT:    movapd %xmm2, %xmm3
 ; X64-NEXT:    divsd %xmm0, %xmm3
 ; X64-NEXT:    #APP
 ; X64-NEXT:    ldmxcsr 0
 ; X64-NEXT:    #NO_APP
-; X64-NEXT:    wait
 ; X64-NEXT:    movapd %xmm2, %xmm1
 ; X64-NEXT:    divsd %xmm0, %xmm1
 ; X64-NEXT:    #APP
 ; X64-NEXT:    ldmxcsr 0
 ; X64-NEXT:    #NO_APP
-; X64-NEXT:    wait
 ; X64-NEXT:    divsd %xmm0, %xmm2
 ; X64-NEXT:    movapd %xmm3, %xmm0
 ; X64-NEXT:    callq fma@PLT

[phoebewang]

Put the check in isX87Instruction?

[Temperature-block]

Oops my bad I accidentally force pushed incomplete changes, will update today sorry for any confusions.

[phoebewang]

Pre-checkin failure is relevant, please check it.

[Temperature-block]

@phoebewang
updated with test-case change, wait needs to be inserted before final instruction in series of X87 instructions or when next instruction is a Nonwaitcontrol instruction which may reset the status registers
Please do let me know if something is amiss from my side,
Thank you

[phoebewang]

LGTM.

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